Strange Pains in Abdomen

So two days ago during intercourse I started having this sharp and painful pain in my lower abdomen, it lasted for half an hour after intercourse and went away. Yesterday I had the same pain while laying down but it lasted only a few seconds and then today I got it again while taking my dogs out only it was on the right side and lasted a few seconds. Im 5 days from projected period, any ideas? I've NEVER had this before.