I have a herniated disc...I went to doctor and told me that I could still lift weights as long as I don't do squats because of all the pressure that compress at the disc.
What is a another alternative for squats, deadlifts, clean hangs?
You can do something like belt squats. But really you won't find exact alternatives to those movements since a lot of them are meant to load the spine and train your back.
There are movements you can do which train those body parts but most of these are isolation movements such as:
I also find the goblet squat much easier on the back than the back squat.
You can also try doing the leg press although you have to be very careful since it is possible to load the spine if you go too deep or your hips start to come off the bench.
Overall I recommend getting physical therapy and getting specific advice from a sports medicine doctor.
Your physical therapist should be able to give you specific precautions and instructions given your diagnosis and/or symptoms. Working with your therapist will give you a clear understanding of what is safe, and what is not safe for you to do as far as weight lifting and other exercise. If your therapist doesn't take you into the gym themselves, they can recommend a qualified trainer who is experienced with training people with back problems. Squats & deadlifts work multiple muscle groups. You may need to target isolated muscle groups for better control at first. Get help from a pro.