I have 4 weeks till duedate, am i having "real" contractions or braxton hicks?

After sex and sometimes during, my entire left side of stomach cramps up soo bad I go into tears and curl up in a ball. They stop after about 5 minutes of relaxing. Also, last night my stomach turned rock hard and cramped up when I was trying to sleep. It was hard to breathe. Even a hot bath didn't help. It lasted about 20 minutes. Im not sure what it is. But they are getting stronger but not more frequent. Please help. I need some answers