Hello
Thank you for your query.
The swollen and painful vagina indicates a vaginal infection in addition to a urinary tract infection.
You should consult your doctor, and have a vaginal swab , specially for streptococcus or any other severe infection.
Keep the area clean and dry.
Do not wipe / rub / clean vigorously.
Have your blood sugars tested.
Also, contractions in absence of pain are usually Braxton Hicks contractions, which are harmless, and are preparatory for labour.
If the contractions cause pain, please visit the ER, as infections can lead to preterm labour , more so in twins.
take care.

Thank you for your Query.
Your doctor is already treating your infection the only suggestion I have is to add metronidazole. Some contractions in the third trimester of pregnancy are normal, so called Breckston-Hicks contractions. However infection increases your chances of going into premature labor. Your doctor needs to examine you to see if you are going into labor or not. If you are showing signs of premature labor the labor can be suppressed. Because you have an infection it would be wise to monitor the fetal well-being. It is important for obvious reasons. To clear this infection before you go into labor. I trust you find this information helpful. And I wish you well with you and your baby.