Wow..that is fast
If you did not gain much weight, then it is not unheard of that one could be losing all that after 1 month.
You must have been working hard on that..Wow. Just don't over do it..Your body needs time to heal/deal with the change of 9-months of pregnancy
. If you are feeling well...Then u should be ok. If not, take it easy and consult doc. Congrats on new baby. God luck.