This certainly could be related to your med's. When I've had problems such as this in the past my pdoc always simply suggested varying the times at which I would take my medication. It might be worthwhile discussing this with your prescriber.

The other thing though is that this sort of thing can, at least from my perspective, easily become a habit. It may be that returning home simply triggers your low mood. In that case, what may be helpful is to find something else to do instead of going home. Or find something you can go back out & do as soon as you get home. For example: join a fitness center or take up running, swimming, etc. depending on your circumstances. Other options might be go to the library, or even to a coffee shop, to study.

What my experience suggests to me is that it is certainly worthwhile to discuss this with your prescriber. But even if you are able to change the way you take your med's, or make some changes in the med's you're taking, chances are until you find some way to avoid simply going home when your classes end, you're likely to continue to struggle with this. Good luck!