Is it possible that I'm pregnant?

I took my first depo shot in September and I never took another one since. Is it possible for me to get pregnant still.. My boyfriend and I don't use protection either and Ive been experiencing nausea at night when I lay down. I also feel extra tired and I can sleep an entire day. I'm having cravings just by seeing food..also my nipples feel like they are on fire..can I be pregnant should I take a test?