FET Anxiety & cramps?

I had my second FET on Thursday & all was well until Saturday evening I had a sharp cramp or pain. It was just like for a split second & then stopped. Then since then I’ve been feeling mild cramps. The type like pre-period warnings. And I’m really worried that it’s my body “knocking off” the embryo away. Have any of you felt that before? Am I worrying about nothing? My blood test will be this upcoming Monday. I don’t want to take pregnancy tests and worry myself.