Have been in your spot -don't let your imagination run away with you. I had a stone. It's inconvenient, but not the end of the world.
Buying test sticks lessens the chances of surprises at results, but there must be a good reason for the blood.
Most likely, I'm told, is a kidney stone. They'll do checks to eliminate other possibilities. If it is a stone, the last thing you want is to lose it (you'll probably know) -having the stone allows them to see what type it is, and it's positive proof of what the problem was. Drink tons (3 litres a day - more with exercise) until you see the quacks, but pee through a tea strainer to catch the stone, if it's small. I'm not joking.
Good luck.