Yes, you need to be VERY worried about getting pregnant. What you did is probably the very worst time to miss taking a pill/s.
The way your menstrual period and pills work is that for 3 weeks while you are on an active pill your body sends your body a message to not ovulate. You can stop taking the pill for awhile and your body still has enough of the pill's hormone's in you that it is still getting the message. But after about 5 days it starts to run out and by 7 it really has very little left. SO while on day 1 you are probably still safe, by day 2 you are definitely not.
Even though you might have started taking the pill on Day 3 - your body may have also gotten the message to ovulate. SO you really have to consider that you are not protected from getting pregnant for the rest of month. It doesn't matter if you take the pill every day for the rest of the month- if your body got the message to ovulate - the pills are accomplishing nothing.
SO what you need to do now is to start using additional protection until you have your next menstrual period.
You also need to take two less of your active pills and start taking your placebo pills two days earlier - UNLESS you want your menstrual period to permanently start two days later than it has.
The menstrual period you are going to have next might start on time or be one or two days late if you are not pregnant.
If your period doesn't start 3 days after you expect it to- you need to wait five more days before you can take a pregnancy test.
When you take the pregnancy test it might be accurate and it might not be. After 5 days a pregnancy test is VERY accurate in telling you you ARE pregnant, but not if you are not. SO if it says you are pregnant you most likely are and you need to see a doctor to confirm it as soon as possible.
If at 5 days you take the test and it says you are not pregnant, you need to take it again in 5 more days. If it is negative both days you are PROBABLY NOT pregnant. If it is negative the first time and positive the next it is very likely you ARE pregnant, but you need to see a doctor to be sure.
Teenagers do not test as well as adult women do. The tests are more likely to be accurate in telling you you are pregnant that you are not. So if both tests are negative you are probably not pregnant, but you could be. So until your next period starts keep your fingers crossed.
Good luck, and now you know the next time, if you are not taking your pill as you should, use additional protection until your next period starts.
Susan