Im doubting her pregnancy

mare is due mid june but she isn't showing at all. no i didn't have her tested, she was covered accidentally by a donkey, and we figured it no big deal. her teats are becoming waxy and when i wash them, milky stuff kind of comes out, but her bags are not swollen. this is her first foal ever, and she is about 15.2 hands, an appaloosa, she has a bit of a long back, but she is very stocky, almost like a quarter horse. she is 7yrs old. I can tell she has obvioulsy gotten rounder, but not like my nanas horses that looked like they were about to pop. she's getting Mare Plus, good feed and knee deep in grass. she seems to be getting fatter because she isn't exercising and stuffing her face, not being pregant. she has become much more moody with the other horses and now she is boss mare when she used to be at the bottom and very protective of her feed.and sometimes the donkey still tries to mount her and she just stands there. tell me about your experiences and ideas, is she pregnant?

From what you describe, i would say she's most likely pregnant. However, have a vet out to be sure. Maiden mares will often not 'show' their pregnancy as much as older mares, and their foals have a tendency to be smaller. Please don't allow her to gain too much weight even if she is pregnant. This can cause all sorts of problems with her health and with her delivery. Fat mares have a higher incidence of problems foaling, retained placentas, etc. than mares in proper condition.