HI Mercury
I am Canadian and lived in the UK for 11 years and have been treated in both countries for this disease. In Canada there is universal health care coverage (like NHS) and you will be covered as long as you immigrate properly. It is not an insurance system like in US. UC should not be a reason not to immigrate.
I live back in Canada now and the quality of care has been good - the same as in UK in my experience.
You should start to treat it - the pain is most likely serious inflamation and everytime stool passes through it will hurt like H*@@!
Good luck to you,
Clicky