I need help

I'm 16 years old, I had unprotected sex on February 12th, I got tested 2 weeks later to see if I'm pregnant and it came out negative. I always thought it would be to soon to tell. Well ever since I've been peeing a lot, feeling sick and drowsy. This would be my 11th week and I gained 10lbs in the past month... But I have no clue where it went. The past 2 weeks I've had this little tummy and pretty much looks like a baby bump. I started the depo when I got tested so that's a major problem here. I don't have a way to get a pregnancy  test so I really need good answers to see if I'm pregnant or just getting fat! Thank you all so much.