Orgasms in first tri

Shawna • Have a 7 year old to a previous marriage... Sched repeat section on 7/22 with #2 with my husband
From what ive read, its fine & natural ... I get some cramping afterwards, for a little while... I cant help but feel like my uterus contracting  can possibly cause me to miscarry. Im sure its 100% irrational to think it, but it always strikes my mind ... Any words of encouragement ... Or thoughts?!( Im 8w5d with healthy baby... Just saw/heard hb 168 saturday )