Hi thanks for your question.
Since you were quite rough while mastubation.Most probably you have injured your vaginal wall or cervix
which has resulted in bleeding.You may have also injured your urethra,which is giving you abdominal cramps.The urge to go to bathroom could be fore runner of urinary tract
infection(UTI) which may be due to urethral injury
.Give rest to you private parts for a week time.so that Injury caused to private parts by masterbation get healed.If cramps remain persistent and you developed UTI
.In that case I would suggest you to consult a physician who may advice you urine examination to rule out/confirm UTI and may prescribe you drugs accordingly
Hope this answers your question.