I've taken 4 pregnancy tests since July 20th (July 23, August 1 & 4) all negative. I'm on birth control but had sex using the pull out method on June 28. I've been worried sick. I did have a period July 16th through the 22nd though. Waiting for Aug period now. My body has been showing some symptoms (slight dizziness, slightly more frequent urination, breast tingling). Is there any chance?