What does it mean if after getting a filling my tooth is very sensitive to cold water? also, there is blood in between the teeth if i scrape it

Very common: A tooth may be sensitive to temperature after the routine dental treatment (filling). Most likely the reason is extensive decay in a proximity to the nerve area. Usually, the sensitivity resolves on its own within a few weeks. Rec: see your dentist if the sensitivity does not subside within a few weeks, or if your get spontaneous toothache.

Cold/bleeding: You had surgery, your tooth was surgerized and repaired. The deeper the cavity, the more extensive the surgery, the longer to heal. As to bleeding between teeth, probably indicates gum disease. Report both symptoms to your Dentist now.