Can my mare be pregnant?

Question
I bought a horse in September 2009.It was in poor condition,underfed,ringworm,hoofs uncared for.I groom her everyday and I had to skip 4 days(bad weather)and I noticed a huge lump on her side abdomen towards the rear.I called the vet and he says she is pregnant.He didnt want to palpate her as he was scared she miscarries,he gave her rino and we had already gave her spring shots the previous month(not knowing)I called the previous owners and they say no way she could be pregnant!She was living with two geldings,and only studded last October 2008.My question is this:How can I tell if this is a false pregnancy(if such a thing exists in horses)The previous owners may think I am angry and are lying.I want to send pictures to you but I cant get them downloaded.She has bagged up,her rear is softer,she bites her sides,the lump will move when I give her fresh cold water.I am having trouble believing that she is pregnant,and maybe she has just reached her ideal weight.If this is the case I would like to be riding her and getting her ecersised(I had to take a little break because she had a limp durring her excerises one day(also could be due to the excess weight).Without being able to send a picture I dont know how you can answer me?Perhaps I can send you one once you respond to the email? Thank you,Carol

Answer
Hi- Sorry it took so long- i didnt recieve the question. It is possible that she is pregnant, but she would be due now!! I had a similar mare and she didnt even bag up and had a foal-She was poor when we bought her and didnt appear pregnant either. If she has a bag and is spongy around her rear- I would say look for a baby- I wouldnt ride her until you find out for sure- False pregnancy is possible in mares. can you send a pic to my e-mail address? heathersboers@yahoo.com thanks