14 , protected sex 2 days ago ,

Hi! Many thanks for your question on eHealth forum!

What you have is probably honeymoon cystitis that happens in females after first contact with sex. Trauma to the genital and the urethral orifice, and bacterial contamination from the fingers or mouth of the either partner makes cystitis prevalent among first timer females.

The most common bacteria that cause cystitis are called E. coli (Escherichia coli). Latex allergy from condoms, ill-fitted diaphragm, contraceptive foam or jellies, herpes and trichomona infection (sexually transmitted diseases, unlikely if the condom did not leak or burst), non-bacterial infection, like thrush, dry vagina and bacteria under the foreskin of the penis among uncircumcised men are common causes.
Drink plenty of water, cranberry juice and follow good personal hygiene before and after sex like bathing or washing the private parts well will help prevent it to a great extent. Get the urine tested for infection.

Pain in lower abdomen can be due to this UTI. Blood discharge could be because of rupture of hymen. It could be also because of infection or injury to vagina.
Since a confirmed diagnosis cannot be given on net please discuss these possibilities with your gynecologist once or go to a STD clinic or a walk in clinic. Hope this helps. Take care!