Is she still eating & well? when was she last out grazing? Lungworm seems to be bad this year, I post mortemed ewe hogs last week dying of lungworm so that's certainly a possibility. Probably best to have a chat with your vet who knows your local disease risk. It was fairly mild up till Christmas so if she was grazing then she may well need a worm dose against hibernating worms, & again depending on your risk, liver fluke. Albex is safe to use in late pregnancy, remembering the milk withdrawal if applicable.