scared to have sex after lifted pelvic rest at 36 weeks

So, my doctor finally said I could go back to normal activities including intercourse since being on pelvic rest since 27 weeks with an extremely short cervix, 2cm dilated & 60% effaced. Even though the doctor said it would be fine to go ahead and have sex, I'm paranoid and worried that I will go into labor right after. All she said was that I may have contractions after, but didn't seem concerned. If we use a condom will it help at all to decrease the chance of that? I just want to go back to normal and do things with my husband before the baby gets here but we are paranoid. Anyone else have a similar experience?