I have a feeling you've had a traumatic childhood. The not sleeping much as a child makes me wonder. I was also like that.

You haven't been on antidepressants too long, yet long enough to know how they are effecting you. I tried lexapro for a very short time and yes was feeling suicidal too when I stopped. But I found antidepressants interrupted my sleep too much. I'm possibly bipolar too. I'm not trying to be your doctor but I'm thinking that the antidepressants might be speeding up your thoughts, at the same time making you tired.

I'm depressed almost constantly so bipolar doesn't fit me either. I'm sorry I don't have any answers. I'm just thinking that maybe you are on too many antidepressants.. but if the tiredness hasn't gone away I guess that's why she added the wellbutrin...
I sure hope your psychiatrist is a good one and helpful.
My therapist thinks I have borderline personality disorder, don't know why I mention that because I know nothing much about you and that's just me.... just saying in all my years all the labels never really helped. Its a tough life, so much harder with depression, and I'm sorry for how you are feeling and hope you get relief and help soon.