Plan B has a high dose of hormones in it which is what helps prevent the sperm and egg meeting.
Some experince some bleeding 1-7 days after taking the pill.
As you've taken plan B twice within close succession, then the high dose of hormones are likely to mess with your periods. Oh, since you used a condom and were on your period, then it's highly unlikely for you to get pregnant from that.
It can take a couple of months for your cycles to return to normal after taking the Plan B pill. Stress is another factor that can make your periods late or even cause them to be missed.
Try to focus on something else and stress about it less as it will help. Some Plan B pills suggest you take a pregnancy test 3-4 weeks after taking it to make sure it's worked and you are not pregnant.
As you are with a boy, and you are having regular sex, and do not want to get pregnant from the sounds of things, wouldnt you be better getting onto some kind of regular birth control like the pill? There are many types of birth control out there apart from the pill. Do some research, and find out which one you like the sound of and then go and see your doctor.
If you dont want hormonal based birth control, then there are only 2 options condoms and the copper coil which is a small t shaped device which is inserted into the uterus.
Hormonal based there are lots, IUD which is similar to the copper coil same shape but releases hormones into your system, the patch, the pill, the mini pill, the implant, injection and the list goes on.
Surely birth control is better than using the plan B pill on a regular basis to prevent pregnancy. You can also use condoms with the other types of birth control so you end up using two types and the chances of both failing at the same time are extremely low.