stomach cramp

My edd is 21 Aug 2019 . Now is only June havent even July. I'm starting to feel cramp . And sometime the cramp is so pain till I need to stop moving and stop breathing till it's gone. Water bag never break . I think it's when baby is moving and choose to kick and push at wrong part but it's making me paranoid. I scared of pain but my tolerance in pain is also quite high . Dunno is this cramp normal to feel it now this early . But I've read online about knowing what shud I expect if I'm ready to get into labour . Some of it are happening to me . Like my back is aching also . I'm so paranoid. I never feel this kind of cramp or whatever my tummy is feeling In my first pregnancy before . Shud I be worried or is it just normal .