Depends on what you know with 100% certainty -- Was the man a client going in for an actual session? Or was the man a family member or friend there to pick her up to drive her home because she wasn't feeling well? And, did she tell you why she had to cancel today?

My mind automatically jumps to your t being sick. I know this flu thing going around is wicked so maybe that person was there to pick her up last session. I don't see it as her not caring about you.

If your t is on the up and up: I think where your t could have done better is to have explained to you that she wasn't feeling well and that her man friend was coming to pick her up at X:XXpm, she had to see another client quickly also, or whatever. She also should have told you why she needed to reschedule today (assuming she didn't). She shouldn't have put you in the position to let your mind run wild with worry and confusion.

If your t is not on the up and up: That would be a pretty bold lie to tell a client they need to cut the session short because they aren't feeling well and then drag another client in for a session right after. Therapy would be a done deal for me if that happened.

I think if you were good with therapy before this all happened, asking your t for clarification on who that man was, what happened that day, and why she cancelled today might be worthwhile for you so you can better decide what to do.