If you are having pain and discomfort in the lower belly and the burning sensations and especially when you urinate (you may also notice blood), it is likely to be a bacterial problem and you do need to drink lots of water and see the doctor.
For a yeast infection, if you feel a discomfort, burning, itching and soreness on the in and on your private area, like Caryopteris says this is likely to be a fungal infection called Thrush. An antifungal cream for the genital area can be purchased from the pharmacist or your doctor can prescribe. There is also a single dose oral capsule called Fluconazole 150mg for Thrush too.
If this is Thrush (a fungal infection) as a home remedy you can apply natural set yogurt to your washed vagina and the area will help. The yogurt will soothe the soreness and also help with any inflammation.
Your partner may need to be treated too if it is a fungal infection as he may pass it on back to you. Men do not always get symptoms. If he starts to itch then you will know that he has a fungal infection. He too can apply the yogurt onto his genitals.
Do not wash with soap as this changes the pH level and can make Thrush worse. Taking antibiotics and not regulating sugar levels in diabetics as well as having a sugar diet can also bring on a fungal problem.
Best wishes.
He could also have caused abrasions to your delicate tissues. This can set you up for yeast growth. An antifungal cream could soothe it. Make sure his hands are very, very clean, and he needs to use a lube on his hands like Silk E or 100% clear aloe vera so he doesn't cause abrasions. You may be too tense to be naturally lubed, and birth control can cause dryness and set you up for yeast infections, which will dry you up.
Sounds like you may have Cystitis. This is quite common with rampant sex. A woman's urethra is much shorter than a man's and bacteria can easily enter the urinary tract.
Make an appointment with your doctor and take a urine sample preferably the morning one. The doctor will do a simple urine test that would show whether you have got a bacterial infection. If so, he will prescribe the appropriate medication for you.
Drink plenty of water to flush out the bacteria. Drinking a glassful of water with a teaspoonful of Bicarbonate of Soda with neutralise the acidic urine which is causing the burning sensations. You can do this 3 times with an hour in between each dose. You can also drink water with fresh lemon juice this too will neutralise the acidic urine easing off the burning sensations.
It is very important that you drink water, 2-3 litres is usually recommended. Even though you have a burning sensation and may not want to urinate, it is important that you keep drinking and going to empty your bladder when you get the urge.