Are there affordable weight loss/yoga retreats in Thailand?

Hi all :) I just got out of a break up, feeling a bit low and thought it is time to get in shape again. I've tried googling weight loss/yoga/fitness camps, but they all seem to be very expensive, a week for more than I earn in 2 months.. If they exist, can any of you please guide me to some places that include board and are inexpensive? Thank you so much in advance and have a great day :)