I'm have all the Symptoms of pregnancy, tender breasts, stomach pains, lack of appetite, headache, tiredness, and fatigue but when I took pregnancy test it came out negative, could I be pregnant or is it something else?

If you have been having sex, yes you could be, but it could be something else. Have you missed any period yet ?

I haven't had a period in years because I've been on Depo Vera

Sometimes your body can carry the Hormone and you might not be pregnant the best thing is to get a blood test