Cramps/constipated... (Sorry tmi)

Katie • Expecting my rainbow baby Jan 2017 ❤️
I am 4 weeks 3 days pregnant. I've been having quite bad cramps for the past two days. I've had a hot water bottle on my stomach which has relieved it quite a bit but it's still there. My question is should I be worried? I have not had a poo for about 5 days and am very constipated (sorry tmi!!) but could that be what's making the pain bad??? :(