Braxton Hicks

Braxton hicks contractions. I got them at around 34 weeks with my first, but I am already experiencing them at 21 weeks this time around. Normal? They seem really intense, and are causing some back cramping and feeling like I need to poop. Tmi, sorry, lol. It's been going on since around 18 weeks. Has anyone else experienced this? Should I be concerned? I've also noticed that my pulse is always elevated. I'm a CNA and check it at work sometimes, and it's always in the 125-130 range when average is 60-100.