I had braxton hicks from 20 weeks on and sometimes couldn't tell the difference between bh and baby balling up... but when you have real contractions you will know. (Everyone said this to me and i said but how?!) Until i went into preterm labor with moderate contractions and i definitely knew!) Try to trust your body and don't rush it :)
Good luck!
Usually when you have Braxton hicks your stomach feels really tight for a couple of minutes. I usually take a deep breath in and out they aren't really painful though. Trust you will know when the labor pains start. It will be menstrual cramps times 1000! I'm also 35 weeks we don't have long to go just hang in there!
Im just about 35 weeks fyi