Thanks for posting your query.
I would like to know if you are breastfeeding
your baby. If yes, then this can act as a contraceptive
and prevent you from conceiving at least in the initial first 6 months.
Please give some time for your body to settle down. It is very common to see changes in weight in the post partum period.
You can continue with the pills, your cycles will regularize in the next few cycles.
Hope this helps.