Infertile on the pill

Megan
I've been on the pill now for 24 days. It made my period 15 days early and I've now been on for 14 days😬I've been getting quite sick two, but never sick within the two hours of taking it. 
I heard that some forms of contraception do not suit people and they still get caught pregnant. 
Is there anyway of knowing the the pill may not be suiting me and I could still get caught?Â