A.R.
You are losing weight because of the milk.....your production has decreased and you will taper off at some point, its kind of like the 'water' weight. most people don't know but we can hold 12 pounds or more of fluid[milk] in our mammary glands while BF.
You need to be patient with the waiting for your peroid, you've not been a month off yet. It takes time ?2months for your hormones to stabilize after BF, you will get it, make sure you continue to use protection.
Good luck.
A.
mom of 3 and a R.N