Yes you guys are right about her miscarrying her foal, I do not know 100% whether it was a miscarriage or late term abortion due to stress or trauma though. The man I bought her from bought her pregnant and threw her out into his herd of horses. The stress and bullying that could have occurred due to that may have been the cause for her losing her foal.
That being said I also have seen some changes the past week such as a softening around the tail area, puffiness in the vulva, very slight amount of reddish discharge, and her belly had been cone shaped up until I took that picture. She had a very V shaped belly but after the foal had a very active day her belly seems to have gotten rounder and wider and I haven't had any foal activity since. Today she's been resting quite a bit and has often looked at her belly, making me wonder if she's not going to surprise me with a foal a bit sooner than expected. I haven't noticed any elongating of the vulva yet, but she's got a fairly long vulva to begin with so I'm not sure if I'd notice any change right away.
I worked at an equine repro vet and was in charge of watching the mares there for signs of foaling, however it is somehow different when it's your mare foaling (she was my first horse too, so she's my baby). I'm not unfamiliar to the signs, but some people have mentioned things to me that can be watched for that I'd never heard before and I am always eager to learn more.
Knowing my mare, I really DreamCatcherArabians' estimate of foaling due date will be highly unlikely, I am starting to suspect she's going to foal sooner rather then later, however it wouldn't be the first time a mare might trick someone, would it? Ever since the first day she was bred I could tell she caught, simply by her attitude. She would be sleeping out in the pasture and would suddenly sit up, turn her neck around, and in the most affectionate way, nuzzle her belly. I have no doubt she'll be an amazing mom.
I will definitely keep you guys posted and have pictures to share soon. Anyone have any advice on the discharge I'm seeing? I have Googled it and everything I can find (barely anything) says that it's normal, however I never witnessed it first hand. It's a dark red colour and there's usually just a drop or two on her vaginal area. Nothing that has me alarmed, just attentive.