Looking for some insite I went to the Er with major cramps and back pain they assumed

It was just a bladder infection or kidney infection well it was negative for both and negative with a urine pregnancy test but they said it could just to early to pick up on the urine test…. So I had to make an appointment with my Obgyn and go from there the pain is literally unbearable my lower back and my stomach literally feel like they are being eating by my body any insite on if that’s what early symptoms are of pregnancy because with my daughter I never had this 🥺