It would be a good idea to go to your doctor or a clinic and get tested. Generally, if you are sexually active you should be tested about every three months or so too.
In the future, it may be helpful for you to pick up some condoms and bring them with you when you go out. You can get some for free from your local Planned Parenthood, but if you have no access to condoms or lube please send me an email at becauseiamawoman.tumblr@gmail.com with your name, address, and story and I will send you a safer sex care package.