On depo but possibly pregnant

Mani

I had my first August 12th and so now I’m on birth control. I got my first depo shot on December 2nd and my next shot is due March 3rd. But I had unprotected sex the second and third week before my next shot is due. I’ve been experiencing bad stomach pain with gas, headaches and sometimes nausea. Can I be pregnant or it’s something else going on with my body.