All the signs but my test keep saying negative.

I was on the birth control Depo shot and didn't get it renewed in June. So it's been 4 months sense I was suppose to renew the shot. At first my period was 3 weeks long, then it went to every week/ every other week up till about Sept 15. I haven't had a period sense, my boobs are tender, my hormones are crazy, cramps, and there's been a lot of discharge. I've taken 3 pregnancy test and all negative.

I know I need to make a doctor's appointment, but I'm only 20 and between working and getting things done on my days off is impossible.

Has this happened to anyone and ended up being or not being pregnant?