Need help with my cat

My oldest cat is having some problems. He is 16, He keeps going to poop and he'll stay in the position for a little while but all that comes out is a little blood. He seems a little sore aroun the stomach area when u try to touch him. My vet isnt gonna be in until monday and i've never taken my animals anywhere else i dont trust anyone else, but i dont know if i shoul wait. Does anyone know what could be causing this? and does he need emergency care rite now? Thank you.

Is it bright red blood and a few drops ?? or is it older dark blood or alot of blood??

its not really bright but not dark, in the middle. Sometimes its drops sometimes its like a little watery and a little more comes out. Usually not a lot.

I would suggest calling the local ER vet... but I think it sounds like something that may wait till monday...

Ok i will call them and see what they say. Thank you