Stress. More specifically stress and the hormones that are trying to help keep you upright I would suggest an increase in water, make sure you are getting all the salt and oil in too. Incorporate a calming ritual that makes you feel more like yourself, an epsom bath with lavender, a walk in nature, gardening, painting, etc. This can’t be a fight with your body, its more of a partnership dynamic. IMHO. Enjoy the journey