help?

I'm on depo could feel my shot wearing off like I do every three months and had unprotected sex a few days before (April 18 and 22) The 24-25 I had light cramps and red spotting after using the bathroom. I never get cramps before my next shot and the spotting was lighter than normal the day after spotting I got my shot but have been having so many different pregnancy symptoms.  I've tested twice but neither were the first urine and both came out negative. Is it possible that I am actually pregnant? Taking a test in the morning to triple check