I agree with farmergirl. You are assuming a lot about his not returning your call. Maybe your message got lost and he never got it. Maybe he had some emergency. Maybe he misunderstand that you wanted to see him that day.

He wants you to be open with him, so here is your chance. I would ask him if he got your call and why didn't he call back. I would call him again if you can't wait until Tuesday to find out what happened. My guess is that he did NOT receive your call, did not hear it clearly, or misunderstood that you wanted him to call back. It doesn't make sense that he wouldn't call you, especially since you rarely ask him to call back.

You don't need to feel embarrassed! I think most of us have times when we need our Ts and sound desperate. There's got to be a logical explanation why your T didn't call back.