Is the pill effecting my weightloss?

Hello, I started the pill almost a month ago. Every month so far i have hit the target of 1 stone a month. Sometimes even losing 2 or three pounds more. Since i've been on the pill ,i've had an extremely nauseated stomach and also I'm losing less than usual. I somehow have to lose 6 pounds at this weigh in to be on target , which is unlikely. Can the pill be causing me to have lower weight loss?
Sorry to be so personal and thank you in advance.