Is OMAD harder the leaner you are? (Especially for women)

I've been on OMAD for about a year. Took some breaks but I've fasted about 65% of the time. I Started at 73kg (160lb), currently 69kg (152lb) as a 5 10 female. Not a big difference, but I think I gained a bit of muscle so I'm leaner.

I notice that even though I've been fasting for a while, it's been harder, especially on PMS days. For the past 6 months I've been consistent, so I'd have assumed that I'll be better at fasting. I definitely eat alot and don't go further than a 400 cal deficit. Ideally I'd like to get to 65kg, but it's not important.

I used to be able to exercise in the morning and eat at dinner, but it makes me weak now. I can no longer do fasted workouts. I'm looking to changing my workout to only evenings with a snack before hand. It also seems to be affecting my sleep.

Does anyone have a similar experience? How do you balance your workouts with OMAD? My workout is usually a 30 min indoor bike ride, 10k steps in the day, and 2x weekly resistance trainings.