Late, cramping

So I've been cramping for 4/5 days now. I usually have a very predictable period. My cramps have gone from very light to sharp to very light on and off now. I was suppose to start according to my apps yesterday but really feel like I should've started on the 9th because of how bad my cramps were that day. My husband and I never use protection and I'm not on BC. When should I test???