Keep us posted! I hope it's not just your body being wonky, and I got you all nervous for nothing
Usually with the estrogen shed of weight loss, you should see more frequent periods or stronger periods (or spotting in between cycle, not instead of cycle), not a lessening intensity, duration, or frequency, which is what made me suspect. However every woman's body reacts to excess hormones differently, and stress/lack of sleep/travel can also affect your cycle and the severity of your PMS.
Big hugs, either way!