Perhaps. I would be lying if I said I cannot believe I am over 40 now, for it seems like yesterday I was in college and it is all so vivid to me. But truth be told I had these periods several times before in my life: at a teendager, in my mid twenties, and then very briefly in my mid thirties. They come on inexplicably. Even when there was no reason to be anxious or down, I dark lull would come over me and last for months, frequented irregularly by these periods of intense feelings of unrest and thrill seeking, which during intercourse would become profound euphoric highs, done like I have experienced in any other fashion. I have avoided even the most casual drug use because I am convinced I would be high risk for dependency in these periods but honestly it is a wonderful intense, brief rush, but almost immediately followed by such a lonely sadness, even when having been with someone. I cannot describe it better and at a lost for why except it being more than just a mid-life crisis or being horny. I really wonder now at this age if I have suffered manic depression and never fully realized it. Thankfully, I can be highly functional even in these periods but at work, I just cannot take social interactions and become quite withdrawn and colleagues have noticed and asked. I just tell them I'm just a bit stressed but damn I feel pathetic for this, like some angst, love stricken teen with all this chaotic energy of highs and lows crashing against the shores of my psyche leaving me so focused and in awe of mere existence itself and wanting almost nothing to do with it the next. Its just not right.