Occasional headache, lump and depression

Recently I have been feeling down; I'll be fine one minute then the next I'll feel quite depressed for no reason then I could be fine again soon after. I have never really had headaches but now and again I am getting them. I am 16 and go to school which I enjoy. Last month I had a lump on my stomach and was peeling for a few weeks, had pencillin and the lump shrunk but now where it was it has turned purple, could any of this be related?
ahamayx