The morning after pill can cause spotting or bleeding after use. And it is not to be used as contraception and should not take more than one in a cycle. You should really research side effects when you take emergency oral contracetives before you take it, know what is going into your body. If your going to be having regular unprotected sex you need to talk to your doctor about a regulat birth control method of use, or say hello to two little pink lines.
The Morning after pill is not 100% for sure. If you are using that as a contraceptive, that can be harmful to your body. If you need a reliable form of contraception, please talk with your doctor about what is best for you. And it is possible that you could be pregnant, I would talk to your doctor as soon as you can, they can probably check for pregnancy and talk about birth control at the same time.