Hi me and my husband arnt really trying to have a baby but we arnt doing anything to prevent it either two weaks ago we had sex and he came inside me and then again 2 times last weak about 2 days ago we had sex and he came in me again but when I went to the bathroom after there was a little bit of dark blood it did that till about 5 pm the next day and then stopped and then last night while we were trying to sleep my low back starts hurting almost like cramps but different some how I finally fell asleep around 4 am when I woke up I had a cramping feeling again and I went to the bath room but there was no blood now about 2 hours ago I went to the bathroom again and there was a little bright red blood and I thought I was getting my period about 2 hours have gone by and I went to the bathroom again and now there is no blood but I'm still having like cramps I am. It due for my period for a weak and a half my period isn't normally like this it's usually regular it normally starts at the same day every month and the blood isn't normally so bright red I usually have it for 4-5 days and I don't normally have cramps please help should I be worried would I got to the doctor