Training in the morning takes a certain amount of adaptation. Most people just aren't used to getting out of bed and 60 minutes later doing something pretty exhaustive.
I'd suggest you look at two different issues here, 1) the tiredness element, 2) the feeling sick.
1) Did you get enough sleep the night before? Did you go to bed at a reasonable time? Were you dehydrated when you woke up in the morning? (did you drink anything?) Had you slept ok the previous few nights? Any of these things can really throw you off your game, especially first thing in the morning.
2) When you do exercise, your body sees it as a stressor and responds by moving blood supply from the digestive system to the muscles to better supply them with oxygen for the exercise demands. As part of this, it doesn't want un-digested food sitting in the gut, so it tries to purge it (as in, making you throw up). Depending on when you ate the apple and banana, your body probably didn't have enough time to fully digest them before the 7am class.
These two are also probably related. If you're feeling sick, then your not going to want to keep going.
For the feeling sick problem, you could try eating less, you could try sipping an easily digestible protein shake (one of the only times I'd recommend one), you could try forgoing food altogether and just having something like a cup of coffee.
When I trained early morning (7am), I'd get up at 6am and have a black coffee and sometimes a banana, then eat properly afterwards. Any more than that and I'd feel quite badly sick and have a terrible training session. Even with that, it took me a good few weeks to get used to getting up and training that soon afterwards.
Don't be disheartened, training first thing in the morning is tough, but keep at it. Make sure you're getting adequate sleep and you'll get used to it before too long.