What Causes Lower Abdominal Cramps Post Menstruation?

Hello. I'm in need of some help. My period came about a week late and it only lasted for 3 days. I got all my menstration symptoms before I started but I didn't bleed as much as I normally do. Well I ended my period a little over 2 weeks ago but I still feel my menstration symptoms. I get headaches about 2 or 3 times a day. I get nauseous after eating and even when I don't eat, it will come and go all day long. I'm always tired, sometimes I'll be so tired that I take 2-3 naps a day and that makes it hard to sleep at night. My lower back and my joints are very very sore. My lower stomach is bloated and even when I try not to eat so much to see if that's it, it's still bloated and its hard to the touch but doesn't hurt, it just feels full. I get slight lower stomach cramps, they feel like my menstration cramps but not as severe, and they only last a few seconds then they're gone again. I'm also eating A LOT more, but I've been craving healthier foods like salads and fruits not junk food, which is definitely not normal for me. My breasts are even sore but haven't grown. But when I took a pregnancy test a few days before I started bleeding, it was negative, but behind the one line it was all pink. I'm not sure if maybe the test was wrong or disfunctionial or maybe I didn't pee on it long enough? Please help.