Could I Have A Serious Problem? (Blood in stool)?

For the past few days I've had a very, very slight pain under my stomach (it is practically unnoticeable) and there has been bright red blood in my stool. It doesn't hurt to use the bathroom, everything else is normal, just the slight pain in (I believe) my intestines and bloody stool. What could this be? Should I not drink alcohol? (was planning to go out drinking with some friends tonight) Thanks in advance.