It is unlikely that you will be pregnant. Loestrin is one of the modern pills that can make your periods very light and short, or even totally absent. This is not a problem, or bad.
I am a bit worried about the way you continued your pills after the delay. You should avoid taking less than 24 active pills in a row. So if you skip the 4 inactive pills, continue with the next pack until it is done. Do not take 7 active pills, 4 inactive pills, 17 inactive pills then 4 inactive pills again. Always make sure you take at least 24 active pills in one stretch.
Take a pregnancy test if you are still worried about pregnancy, but do not expect a positive result. If your period stays away for 3 packs of pills, see your doctor to make sure nothing else is causing it.