If it was only a one off a couple of days ago, that does not necessarily mean there will be blood on a test you do today or tomorrow. It may simply have been a cut or something that happened to bleed that day and it might be completely over and done with now.

Even if it is not and you do get a result saying there is blood in your stool, that doesn't mean there is likely to be anything seriously wrong. Many, many things can cause blood in the stool or rectal bleeding, from a cut to hemorrhoids to a polyp (probably on the more unlikely side at your age) to an infection, to constipation or diarrhea, to Crohn's, to ulcerative colitis, to cancer (though the last would be extremely unlikely at your age). A number of those things would also cause loose or soft bowel movements (some infections, Crohn's, ulcerative colitis, etc). It is even quite possible for the softer bowel movements to have led to the bleeding, if you had to wipe a lot as softer movements can sometimes be messy.

A couple of years ago, at the age of 40, I had rectal bleeding (almost daily for over a month), weight loss, occasional loose stools (once or twice a week) and trapped wind. The consultant said that if my mother came in with those symptoms, he'd be concerned about cancer but that at my age, while possible, it was the least likely option and I would be "the unluckiest person in the world" if it turned out to be that.

It turned out to be hemorrhoids, as we all suspected, probably combined with the effects of my thyroid medication and probably the stress of the whole thing.

Given that you are half the age I was then, that you don't mention weight loss and that you only had one incident of rectal bleeding (very common and usually nothing at all to worry about), I would say the odds of anything serious in your case are even lower than in mine.

You are doing the right thing by getting it checked out, but the odds are high it's something very minor.