Thank you for writing.
It's not coma, and damaged minds can heal.
(My brain has been through so much. I've gone from completely broken to completely healed beyond any expectations. It takes a year for full recovery. I swear it's like having a new brain.)
I understand you say you are awake, but not fully alert, more like semi-awake, or tired awake. (Sure sounds familiar. I've been there.)
The cause could be many. Maybe low blood sugar. See if eating some chocolate helps.
Or not sleeping well. Ask someone to check while you sleep to see if you stop breathing and then after 10 - 20 seconds wake up to gasp for air, and immediately go back to sleep. Sleep apnea. Can sleep all night and wake up dead tired, because actually person is waking up many times an hour to gasp for air.
Or certain medications may make one lethargic. Discuss with doctor. There may be a different med one can switch to. (Or in my case, add another med to counteract the sedating effects of the one med that works for me.)
Just know from my extensive personal experience (which I wish I didn't have because it was really bad, and lasted a long time, but since I've had it might as well make use of it) this is not a permanent condition. Recovery is possible. Doctors can help figure out what is causing this.