Please relax. Symptoms like these do occur occasionally in any menstrual cycle in case of stress
Please check if the bleeding continues. If yes, then this is your normal periods. If it does not continue, wait and watch for a week.
Your urine test has come negative. Therefore, chances of you being pregnant are very less. I do not think it is miscarriage
Please meet a gynecologist if things do not get better in a week.
Get well soon.