Is labour nearing?

Im 38 weeks pregnant. About 24hrs ago dh and i had sex, today i have had alot more pelvic pressure, i have the urge yesterday and today like i need to do a poo but cant get anything out, and just recently had about 5 really quick sharp pains in my pain. They didnt last anymore than a few secs. Any suggestions on what this is all about? Is labour nearing?