Birth control question

I had my son October 28th 2016

Im exclusively breastfeeding so I'm currently on the mini pill. I had a period December 14th and I haven't had one since. I have taken my birth control EVERYDAY. I know it can be normal not to have a period on the mini pill but there was a few times I was a couple hours late taking it and I've been feeling nauseous the past few days. I know that can be a side effect of the pill though. I should be okay right? Has anyone gotten pregnant on the mini pill? I'd be happy regardless but preferably I'd rather wait awhile before having another because I have my 3 year old and 3 month old and I want him to be the only baby for awhile.