39+2 weeks! Contractions?

My contractions are anywhere from 12-15 minutes apart, lasting about 30 seconds each. I was told 4 days ago that I was entering the "first stage" of labor, which could go by really fast or REALLY slow. Which, I'm assuming, slow is my case. 🤣 But, when I have my contractions, some of them give this sharp pain/crampy feeling in my bottom, like I need to poo... but if I did, it would probably hurt (even though half the time I don't really have to). Is this feeling normal? Like does this start happening as I gradually get closer to the other 2 stages in labor? When I was told I was entering the first stage, the contractions were right at about 20 minutes apart. Thanks ladies!