Periods of severe depression?

Is it normal to go through periods of severe depression, and then at other times feel extremely happy about life... So usually I am a very happy person, I party a lot and make memories with some cool people, im also good in the love life compartment but recently ive been feelings really down about a couple things, for example I have no job, havent had one for quite a while but i've been actively trying to find out, the thing is people joke a lot about me partying and not working, and although I laugh it off.. it really hurts.. and it doesn't help that I hate my major in college and feel like I just might be jobless even after graduating... Recently i've been super down and insecure, I always second question things I say, I cry because I have no true purpose of life besides just being here and living off of my parents... I no longer seem to even be attracted to people, well of course I am physically attracted to people who are appealing but I never pursue it, and then when people pursue me for relationships I totally get turned off and ignore them, for no apparent reason, I just decide in my head I don't like them or that they're not my type and truly feel like a unwanting feeling towards them... lately i've been slummed and I feel like this happens to me more than often.. I will have a really good couple of months, then out of nowhere get nailed with the most horrible deepest depression, even worse when I see everyone accomplishing goals involving talent and knowing I really don't have any talent... is it normal to go through periods of depression like this?.. and does anyone have a similar story to share?