Are these symptoms of pregnancy?

I am 19 years old. My husband and I have been trying to get pregnant for awhile now. I was having real heavy bleeding for like 3 years then 4 months ago it just started turning into light spotting for like 1-2 days. I am tired all the time. My back hurts. I have diarrhea some days. Then I can be constipated for a couple of days. I have been having pains in my stomach, sometimes its every where. But most of the time its random spots. Mostly, on my right side near my belly button. I took a test exactly 2 1/2 months ago and it was negative. Should I take another? Or are these symptoms different. I am scared and dont really know what to do.