Think I'm pregnant

April
I been getting really bad cramps,lower back pain, been bloated, and feeling sick at night time. The cramps seem to get worst at night. I took a pregnancy last Monday but it came back negative. Last night, my boobs were very sensitive and nipples. My nipples kept getting swollen. They would swell up then go back to normal then repeat. My cramps were really bugging me as well. I started taking Seven Seas trying for a baby. Could this just be bad side effects or could I be pregnant. I'm not suppose to get my period for another 10 days. We been trying 5 years