I wouldn't jump to conclusions about the cause - yes it could be related to being trans, it could be related to hormones, but it could just as easily be related to fluctuations in diet, what types of food you eat, how much you exercise, how much sleep you get, stress with school or with family, body image, serotonin levels, genetics, etc. etc. etc. And it could very well be a large combination of things.
Everyone has ups and downs. We only see other people in public, so we nly see what people want others to see. A person could be at the brink of an emotional breakdown and appear to be perfectly stable and happy when you see them at the store or in class. The point is, these feelings are most likely extremely normal, just very hidden.
I even have days like this now and then and I'm on meds for it. I know I have things to do like laundry, dishes, trips to the bank to deal with debts, but on my days off, I sometimes just end up sitting around doing nothing.
I think to get over these episodes, you just have to give yourself time to breathe, not stress about the tasks ahead (even if those tasks involve getting your shoes on and heading to the coffee shop to meet a friend) and take one thing at a time. Go as far as leaving your room to go to the kitchen, grab a bite, then get your shoes on, pace around if you have to. Then when you're psyched up go out and do whatever you planned to do. Days like those literally are one step at a time. I find once you're up, once you're moving and out of the house, the rest gets easier. You just have to take those first steps out of the funk.