please help can't poo

I've got something wrong with my back doors and the doctors gave me a hemmeroid cream (piles) but never checked... after two weeks of constant use it's worse than ever I can't even pass wind without it making me tearful so I haven't gone for a poo for 4 days... im not constipated I just physically can't deal with the pain, the last time I went the whole toilet was filled with blood... please all I want to do is poo but I'm to scared and doctors are closed till Monday (uk) I don't know what to do