Pregnant?

Could I be pregnant? I missed my period by 5 days. My boyfriend and I don't begin sex with a condom but always end with one. He even noticed my breasts being much larger than normal and they're very sensitive. I've been having cramps but they're not the same as I'm used to. Not to mention I've been quite nauseous lately and it seems like everything I eat makes me feel sick. What do you think?