Sore lower stomach??

sam

So this I woke up to cramps around 7 am and I just blew it off as nothing. Went through the day doing some light cleaning in my room. As the day went I've start to have like this constant dull pain in my lower stomach. Does anyone else have this or know why it happens?? I'm 32 weeks today with my second baby. My first was full term at 39 weeks and I never felt this before.