I've been through this before, with my last pregnancy, I'm pretty sure it's braxton hicks. The last trimester of my pregnancy (last time) everytime my dh and I had sex I would have what felt like strong constant contractions for hours afterward. I went to the labor and delivery I don't even know how many times. I would go to sleep or take a shower (warm showers seemed to help a little, not much but a little) and I'd get up and they'd be either completely gone or not as consistent as they were before. Sex always seemed to set them off. You know they say it's a good way to start labor but I just found that it was a good way to make me uncomfortable. lol.
Your best bet though is to keep track of them, make sure they're not getting closer together.
When you have them does it feel like they're mostly in the lower part of your stomach or do they radiate from back to front. The ones I had that were false labor were mostly in the lower part and in well, they moved into my crotch area. I know TMI but I'm trying to be accurate.
and of course when in doubt call your doctor or visit labor and delivery.