you should be perfectly fine providing you've been taking your pill correctly as you say you have been :) the "dosage" of pills isn't anything to worry about, they all work in the same way - preventing ovulation, thinning the womb lining to make it harder for an embryo to attach, and thickening the mucus so sperm can't get past the cervix as easily. it seems to me that levora isn't a "low dose" - it's simply that it contains 0.15g of levonorgestrel, which is used in the morning after pill/emergency contraceptive pill at a higher dosage.