Holly vomiting blood

My ex-racing greyhound Holly has vomited frank blood before and we took her to the vets straight away. He prescribed her cimetidine which worked very well and he said that if it continued that it would need to be investigated. He thought that as she has a very sensitive stomach and we had trouble finding a food that suited her when we first got her and she bolted her food down, that she had a little tear due to the vomiting which is why he prescribed cimetidine. Anyway it worked and she had the odd vomit but nowhere near as many and she started to put weight on which was needed. No more bleeding either.
We got in last night and fed the dogs. She ate ok. She's on CSJ lamb and rice with a bit of chappie to help her gain weight. However after 10 mins she started to vomit. The first vomit was just food, then she vomited so hard that she started to bleed again. She has vomited about 4 times...all blood. She isn't ill apart from the vomiting blood. She's not distressed at all, she's not panting. In fact she looks perfectly ok! She's had no diarrhoea...just normal looking stools.
I've been awake all night keeping an eye on her. Our vets opens at 11.30 so I'm taking her in then. I was going to call the on-call vet but in view of her not being distressed or particularly ill I decided I'd rather wait to see my own vet as he has dealt with her before and knows her and is very good.
Has anyone else had this problem and if so, what did you do to prevent this from happening again?
I'm dreading going to the vets in case it's a tumour or something
I was told by the rescue when I got her that she may have been given steroids when racing. If this is true then she may have a damaged gut which would explain why we're having trouble getting weight on her. She hasn't lost weight but has only gained 1kg since last december. She's 24kgs and the vet said she should be about 27kgs.
Any help really welcome!

Sorry to hear that Holly is unwell. The only experience I have had with vomiting large amounts of blood was with my Great Dane who had cardio myopathy. I hope that your vet can give you some answers, let us know how you get on.xx

So sorry about your girl Could it be an ulcer? No experience of anything like it myself, but wishing your girl a speedy recovery xxxx

Good luck at the vets and I hope Holly is ok.
Hopefully something simple like Cimetidine will sort her out.
Let us know.

Thanks all of you. She seems to have settled at the moment. Trouble is she gets terribly car sick and she got to go in the car to the vets! So it's all going to start again now she's settled Poor little mite...she's only 4 and she's got so many problems. I'll let you know how we get on xx

my grans yorkie had this he was really bad the vet tested him and it turned out he had food poisoning. he must have ate something when he was out as he gets off his lead. he was fine after about 4 days. i hope it turns out to be something like this and not what your thinking

Everything crossed for Holly, hon

x0x0x0x0x

Got everything crossed for Holly, hope you get a diagnosis soon and that she is on the mend.

Gentle hugs for Holly, if she'll accept them. xxxxx

Hope the vet finds out what's wrong and Holly is soon better x

Hope Holly is feeling better, good luck at the vets hope everything is ok.