Passing blood in urine / stools / vomit is NEVER a good sign. Especially when it's painful.
You say you can't go to the doctor before next Thursday. Is this because they don't have appointments, or because you're busy?
If it's the former, doctors ALWAYS have emergency appointments. Phone up at 9.30 in the morning and book one there and then (you don't have to say why, but it may help your case if they seem reluctant (Receptionists - like your doctor are sworn to confidentiality about patients) )
If it's the latter. Just cancel something / put it back. NOTHING is more important than your health. Simply, if you're not halthy, you're going to miss out on a heck of a lot.
Hope this helps!