Why do i keep having an eye bleed and how to prevent this?

Depends where: I assume you are referring to a blood spot on the surface of the white of the eye called a subconjunctival hemorrhage which is benign. It usually occurs from coughing, sneezing or rubbing the eye. If it is recurrent a fragile vessel may just become reinjured. It is usually nothing to worry about and should resolve with time.

Subconjunctival heme: It sounds like you are having frequent bruises on the white part of eye ( subconjunctival hemorrhage). Often these are a result of rubbing the eyes. Other causes: sneezing, coughing, valsalva, blood thinners, chronic allergies ;/or dry eyes. All these are usually infrequent, but unusual causes are due to bleeding/clotting problems. Fortunately most bruises r self limited ; infrequently cause issue.