Late period

Salina

So I’m 3 days late on my period. Should I take a test? Yes we been trying to conceive for a little over 5 months now and I’ve took 2 pregnancy test in the past that where both negative. Help me what should I do? Also I’ve been having really bad stomach pain every time I eat. So I haven’t been eating as much because of that. I’m getting very constipated as well with some abdomen pain???