A beta hcg blood test is very accurate and can detect even tiny amounts of pregnancy hormone. So if you did a test and it was negative then I'd say you aren't pregnant. Symptoms aren't reliable, I'm 6 weeks pregnant and have no symptoms. Hope this helps. If you're worried, do another blood test.
The depo deff made me gain weight and kinda look pregnant. I haven't had my period since beginning of October and still need to get in doctor. Have symptoms but pee test cane up negative about a week and half ago so I need to take another .. But good luck to you