Help?

I've been having back pains (feels like muscle aches, but normally they don't last but for a day. These have lasted for about three days), swollen boobs, fatigue, and increased hunger. I spotted for a couple days when my period was due (I was supposed to get it around Sunday 8/11) and it stayed pink to light red and never filled up a pad. I've been on birth control since December and I'm not sure if it failed. I haven't taken antibiotics, but I know I haven't been taking it religiously at the same time for about two weeks. I used a FRER test the day before my period was due (8/10) and it showed negative. Did I test too early or am I losing my mind? My boobs have grown from C-D to almost DDs now. I've never had that happen