Am I pregnant or just being paranoid?

My cycle is unusually long (40 days give or take) and about two weeks ago I had intercourse quite a lot with my boyfriend. I took a pregnancy test yesterday (exactly 14 days after the last day we had intercourse) and it was either negative or a very very VERY faint positive. I looked very long and hard at it and maybe saw two lines? Idk the test was a dollar store brand with blue dye so maybe my mind was playing tricks. I've been extremely tired, every evening about 8 or so I start to get nauseous, I've been breaking out, I have an odd craving for pumpkin seeds and spinach, I've been experiencing an increase in discharge, Thursday I had some brown spotting that was so light I'm even surprised I noticed it, and my period is 4 going on 5 days late. Should I take another test? I should also mention that I'm only 17 and extremely stressed out so... please help