Make sure you're getting enough sleep, and if you can, try to stick to the same sleep schedule. Also make sure you're eating healthy. And I know you said that it's hard to get the drive to exercise, but when you're exercising regularly, it's usually easier to fall asleep and you'll wake up feeling more refreshed in the morning, and hence, have more energy. It's all a big cycle really.
I've only been on T for about 3 months, but so far it's actually made me need to sleep more. I've read that this happens sometimes, as it's a second puberty. So when you first get on T, don't expect to have a bunch of energy or anything. Not saying that it won't happen, cos it could, but don't expect it. Maybe someone who's been on T longer and is out of the puberty stage can have some more insight on energy levels. So far I haven't noticed anything aside from sleeping more.