A heavy or otherwise wonky period is one of the side effects of Plan B. So there is a good chance that you don't have anything to worry about there.
But if you're having unprotected sex simply because you don't feel like using protection or because you forgot to use protection, then that
is cause for concern, even if it's only happened a couple of times.
Truly being ready for sex means being willing and able to be protected by a reliable form of birth control
every single time unless you're trying to get pregnant and can provide for a baby. Plan B is not birth control, it is not as effective as birth control, and it is not meant to replace birth control. There are many different birth control methods available though. Many are very effective and easy to use, and you may even be able to get them for free or lost cost at clinics like Family Planning or Planned Parenthood. So it might sound harsh, but there really is no excuse for not using birth control unless you're actually trying to get pregnant.
So:
-Don't panic; you're probably fine.
-Keep an eye on things and schedule an ob-gyn appointment if your period still seems unusual after a month or two.
-Take a pregnancy test if you want to double check since, while it's not the norm, some women do bleed as if having a normal period during pregnancy and since Plan B isn't 100% effective.
-Don't have sex again unless you're sure that you're
truly ready for sex and all the responsibilities that come with it. Again, part of being truly ready means making sure you're protected by a reliable form of birth control
every single time unless you want a baby and can fully provide for a baby. If you feel ready but you're also sick of using condoms and don't need the STD protection, then talk to a doctor about your other birth control options. If you don't have health insurance and/or don't want your parents to know that you are sexually active, then you can go to a clinic like Family Planning or
Planned Parenthood. They can give you paps, birth control, pregnancy tests, information, STD tests, and anything else you might need for free or low cost.