Hi
Myself have not long ago had the same problem with my staff being sick, refusing to eat or drink at all, being sick very regularly and ( sometimes blood would be in the vomit but wasn't a main symptom like the rest) so I took to local vets and she was given a injection to sedate her and later on in the day, I got told that its ok to take her home but she was given some tablets and since that, no problems with her health. But you NEED to take to vets ASAP and if you cant afford the vet fees then you could be able to go into PDSA which will just ask for donation that you can afford £5 is OK but you need to be in receipt of Benefits and housing benefit?
Good luck