I have a question about my puppy. She is going to be three months is a couple of days. Today I have noticed that she has stopped eating and drinking as well. Then later on in the night around 2 in the morning I went downstairs and noticed she either vomited or had diarihia which had some blood in it. I'm worried and not sure what to do?

I would take her to the vet immediately.

While not eating a meal or 2 is normal for a puppy, not drinking is worrisome.
Combined with the diarrhea she could end up dehydrated very fast.

If you can, collect a stool sample to take to the vet with you to be examined.
There are several things that could be wrong and if I told you I would only be guessing.

I'd put my money on parvo if she has not been vaccinated. The best thing you can do for your pup is to get her to the vet asap and get her taken care of. If it is Parvo they will need to put her on IV fluids and keep a close watch on her for a few days.

A severe parasite infection can also cause these symptoms, and unless they are treated by a vet, like Shazzy mentioned she could dehydrate and die very quickly. In the mean time I would go out and buy some Pedialite and offer it to her, if she will not drink on her won, use an eye dropper and drop several droppers full at a time. Use small amounts but consistently through out the day.

Good luck and please keep us posted.