Pregnancy symptoms dont usually start until about 2 weeks after conception.
It may be because you are going to be ovulating soon. I always get cramping right before ovulation and a little bit of spotting as well. I would say that right now is not a good time to be having unprotected sex if you are ovulating and not trying to get pregnant. If you are trying to get pregnant this is a great time. I don't think it would be pregnancy at this point but do a pregnancy test if your period is late. Just know too in the right kind of cervical mucus (the kind that reminds you of egg whites and normally happens around ovulation) sperm can live up to 5 days so if you had sex yesterday it is possible for conception to happen 5 days later. I hope everything works out ok for you.