You could have an infection in your urinary system (UTI). Some­times, this occurs after intimate re­lations. Signs are needing to urinate­ frequently yet little­ comes out, and potential discomfort. Be sure­ to consume ample fluids and try to urinate following intimacy. Cranbe­rry juice may aid. If symptoms persist, antibiotics might be ne­eded.

Even though you have the condom on, some STIs can still be transmitted, such as herpes or genital warts. Signs could be pain during urination, unusual discharge from the vagina or penis, sores, lumps, or itching around the genital area. See a doctor for testing if any of these symptoms show up. 

Not recommended long term self medication for prolonged sex. This condition can have several causes including stress, anxiety and health complications .Please visist an expert in sexology to specify the underlying condition and give proper treatment. Do not use over the counter or online medications because they may result in serious side effects.

Premature­ ejaculation happens when a man orgasms faste­r than desired during intercourse­. It means ejaculating within one minute­ after starting sex. Many factors can lead to this. Fe­eling anxious or stressed contribute­s. Medical conditions too. However, the­re are ways to manage it. Re­laxation techniques and condoms reducing se­nsitivity help. Seeking the­rapy is another option. 

You have premature ejaculation. It is the time you cum too fast while having sex. It can arise from stress, anxiety, or low experience. Try to be calm and act gradually. You may also want to change positions or discuss it with your partner. It is normal to have this problem and you can learn how to control it. 

Metronidazole is a cure for infections, but it is not used to prevent sexual infections. Unprotected sex could be avoided by using birth control. Sexually transmitted infections can occur by germs that are transferred during sex without a condom. Proper use of protectors such as condoms and regular medical check-ups should be covered. You can also see a doctor who can give you the right medicine if you think you are infected.

Considering the circumstances, it is improbable that your girlfriend could become pregnant if there was no ejaculation. Nevertheless, it is good to realize that any genital contact has some risk involved. Therefore, if she starts experiencing any unusual signs like missing her periods or having abnormal bleeding; I advise you to go for a pregnancy test so that you can be sure about everything.