Did I make a mistake?

Today Sir told me that he has to do something with his boys tomorrow evening, during the time we had planned on being together, and I expressed my frustration at that and at feeling like I am a very marginal part of His life when he is such a huge part of mine.
I am not sure I should have expressed this frustration  but I just could not contain it. It was the final  push over a cliff that has been this week.
I am frustrated at the fact fact hat I am not supposed to be doing anything, my leg is feeling better, but my hip and back hurt when I am up to long because of the difference in my leg lenghths.
I had just found out that one of my favorite students from California died on Monday and then Sir tells me that he has this thing to do. I was overwhelmed, I think I am falling into a depressive funk and I am Not sure how to stop it.
I thought I needed to tell sir how I felt. I know this too will pass, I believe that I am important to Sir. I know that this lack of seeing him will pass. I do not think he is happy about not being able to see me any more than I am happy about not seeing Him. Hopefully He is reading my blog and will see how I am feeling and why.
I love Him as Submissive loves her Sir, which is different and in some ways deeper then as a woman loves her significant other.  He is a very important part of my world even as distant as He is. More by need then want I hope.
I can only hope that he is as committed to U/us as I am even through my frustration right now. WE CAN DO THIS.
No relationship is with out its frustrations and struggles.
I truly care about this Man, I believe he can be the Dominant I need and bring out the best in me.
With a bit of aprehension and confusion as to how W/we are.