You've already started out with the wrong mindset. Essentially, you need help, but you refuse any help that doesn't meet the criteria you want--even if it is the right answer. The bottom line is this:
Nothing works forever.
Starting Strength, while a great program doesn't work forever--and it's not meant to. The same goes for any other strategy. The stronger you get, the more you will need to change strategies. There are several reasons why people hit a plateau, which simply means they need to change something.
Possibility 1: Too little training stimulus
This can simply be put something heavier in your hands and lift it. Or it can be more sets and reps. Or more training days. It's a possibility if you only lift once a week.
Possibility 2: You are doing too much
If you constantly grind at 90+% of your max, you are going to feel bad all the time. Always fatigued. Never clear-headed. I ran into this myself last year after grinding my squats too often. Back off the intensity, and live in the 70-80% world for a while. While you are at it, perhaps cut back on sets/reps.
Possibility 3: Too much focus on myofibril or sarcoplasmic hypertrophy
This affects all strength athletes. Bodybuilders want more emphasis on the sarcoplasmic hypertrophy while folks who want to lift the heaviest total want more myofibril hypertrophy. Bottom line is you need both to keep progressing. Larger muscles have more capacity for strength, mainly because they can supply more energy to the lift. More body mass moves more weight. It's simple physics when you look at potential and kinetic energy, and transferring that to another object. At the same time, you can't neglect the protein pairs that actually contract to move stuff.
I know you said you don't want to do sarcoplasmic work, but it may be what the doctor ordered for now.
Possibility 4: Overtraining
If you've ignored fatigue levels for far too long, added new stresses in your life (outside the gym), then it's possible you have crossed the overreaching threshold and fallen into overtraining. Common symptoms of overtraining include irritability, fat gain, regressing in lifts, anxiety, loss of sleep, and/or depression.
If you seriously think this is you, then take some time off away from the gym. Don't think about training or going to the gym until it is calling your name. It might take a couple weeks, or it might take a couple months in the worst case.
Possibility 5: Lack of training focus
Your body responds to the demands you place on it. There comes a point in time where in order to progress, you have to focus your energies in one direction. This is where strength athletes start specializing in bodybuilding, power lifting, Olympic lifting, or strong man style training. Then you do the work that is necessary to get better, and only that amount of work. Even folks who successfully cross train, their energies are focused on one discipline at a time.
Possibility 6: Diet, Recovery, and Environment
The more you lift, the more you need to eat to support the lifting. That doesn't mean go out to McDonalds and eat 5 big macs a day. You'll need sufficient protein, fat, and carbs to support the activity. The old standby of 1g protein per pound body weight is more than you can use, but it will assure that you have enough to build muscle. Testosterone is manufactured from cholesterol, so you'll need to make sure you have some dietary cholesterol in your fats. Carbs are energy, and you will need a lot. If you make healthy choices, and try to minimize inflammatory foods, you can eat a lot more than you think and not get fat.
Another recent issue come to light is xenoestrogens such as parabens, phthalates, etc. Xenoestrogens are environmental chemicals your body absorbs either through the skin or through eating that throw off your normal body chemistry. Estrogen receptors in the body react to them and they are stored in your fats. Parabens are common in grooming products, but are fairly weak so not a major concern. Phalates are in plastics to make them softer, and get transferred to your food when you heat the food in the plastic container. Most pesticides have the same effect, so make sure you wash your fruit and vegetables before preparing them. If you switch to glass containers to store and heat your food, that can also make a good difference. Of course, organic proteins (chicken and grass fed beef) that are not injected with hormones are also better sources of food.
The bottom line here, is if you keep putting garbage in, you can't expect it to help you get strong.
My assessment based on the information I have
I see signs of possibilities 2-5. Since I don't know what your training regimen is, the fact that you don't want to hear about doing sarcoplasmic work, the fact you always feel fatigued and your social anxiety disorder seems to be intensifying, and it doesn't seem like you have a specific focus you've got a lot going on. I recommend taking a break at least for a couple weeks, maybe even a month. When you get back, change the way you've been training. It's not working anymore.
Find a good focus, and a program that someone knowledgeable in that discipline wrote. Stick to the program as it's written for at least a couple months. If you feel you need to make slight adjustments then, do it.
NOTE: strict dumbbell curls are a great exercise, but they will do you better if you keep it relatively light and do high reps with them. That will help get blood flowing through your elbows and prevent or correct inflammation.
