Was on depo... might be pregnant?

I was on depo for a little over a year. Towards the end I was being celibate for 3 months in December I was supposed to get my shot but I decided I wanted to change my form of bc. I just moved in with my boyfriend and we've been kind of iffy with the whole condom thing. Some of my friends have been telling me to get a test. Well today I started thinking I started my period but I'm only very slightly spotting and I'm not completely sure. Could I be pregnant?