I am on Loestrin also. Assuming it is the same one, which is the 24 day pill (so only 4 days of the "period" part of the pill). I missed my period also. According to the doctor that is normal with this type of pill. I don't like it, it worries me too much. I was cramping a lot so he had me stop the pill 2 days early. I ended up finally getting my period and it only lasted for 2 days. So like I said, this is aparently normal when on Loestrin. Im going to go on the generic of Loestrin, Junel Fe, which worked for me in the past and I think its 21 days of the pill and than 7 days of the "period" part. As much as I dread my period, it's a reassuring thing.
Everyone is different, but I would be lying if I said it's not possible. I was on birth control and my hubby and I used a condom and now we're prego with # 2 :) and if you took the test to early you could get a false neg. in fact a lot of women have that happen. I've had that happen. If you still don't get it in a couple days I would test again or get a blood test done. Good luck