What are your experiences with sex starting labor? If it has, how long did it take?

My husband and I have been having quite a bit of sex and the last two days I feel soooo horrible after. Lower back pains, period like cramping. It makes me think something is going to start happening and then it slows down/goes away. Now I’m wondering if it’s worth having sex if Im just going to feel horrible for most of a day and nothing comes from it!