My new bloods came back and one of the doctors from my surgery phoned me. When she heard it had been two months since the problem started, she phoned around and got me admitted straight to hospital. I had an ultrasound the next morning. I've got gallstones; I've got an ERCP on Tuesday and will hopefully be having my cholecystectomy (having my gallbladder removed) sometime this upcoming week too. The doctor who has been seeing me throughout this also phoned me up (after the consultant from the hospital phoned her) and said she's very glad it's all sorted now.
Also on the blood situation, I did phone the National Blood Service after my original post and they stopped my blood from being used as well as deferring me from donating for 6 months. After I've had my surgery and everything I'll probably phone them up again to let them know what's going on.