It's just too hard

I'm 20 now, and since i was 13 I have dealt with chronic depression. It comes in cycles so I'll be good for a while, staying afloat, then slowly go back down. I also have recently been diagnosed with fibromyalgia, pain medication has helped greatly but the crushing fatigue is a different beast.
I've felt for a long time like i'm just not made for the world, everything is too hard.
I am once again, overwhelmed and exhausted with life. Uni, practical placement and not being able to eat due to the money lost thanks to placement, household chores, social life, taking care of myself, it's all too much.
i JUST had last week off of EVERYTHING to try and get better, and now that im back, im right back in that slump.
The only thing getting me through right now is that it's not forever.
I don't know how I will exist as a functioning adult in a full time career when i can barely do it now. I don't think I can do it.
I dont know what i'm expecting out of this, maybe advice on how to manage stress and stay afloat, but it's really just a vent into the aether. . .