No signs, no AF

I was just wondering if any of you, who have been pregnant before, have ever had cramps before finding out you were pregnant? I have had no other signs except for the this past week or so I've had what feels like Af cramps. AF is schedule to arrive in 3 days. This is our 4 month TTC. I never usually have cramps like this before my period so I was just wonder if this could be a good sign?