Question about eye problems?

ok yesterday i woke up and my eyes were sorta red...when i went to school they were redder and stayed that way until the afternoon...my stepmom said my eyes looked bloodshot....today they were better but still sorta red...i dont think i have allergies from anything.....i do have a problem with styes but the eye that gets red doesnt have any styes right now.....how do i keep my eye from becoming redish colored??