Julie, welcome to the forums!!!!!!
I understand your doubts. Sure you are wondering is it the depression itself or there’s more. You can’t know for sure until you get time pass by. Depression is a dark deep hole and your boyfriend surely can’t deal with anything now. Depression consumes all your energy.
I think it’s awesome that you can be by his side and recall him from time to time that he can count with you and you showed lots of compassion by wondering yourself about what’s the best for him and for him not to feel pressure.

Said that, when a prudential time passes by asked him about your relation because you have the right to know if it’s worthy for you to be there. Depressed people are very hard to deal with, I’m one of them and I know it. So, at least, you have the right to know if it’s worthy to fight for him or the best for you is to follow your own path.
You also have to think about yourself.