no presentation = interrogation

Today, I went into lab. (Evil test tomorrow)
I went to split my cells so that sometime this week I could transfect my cells and prove to my collegues that I am actually capable of transfecting despite my occasional stupid mistakes.
Anyways, I went in and splitted my cells. I went to the computers to check my e-mail and 2 of my collegues were there. One of them was the Post Doc manager of the lab. Just 3 days ago I had to exchange presentations dates with him because with all the stuff that has been going on with my transfections and the fact that I have a test tomorrow I told him, "It will be impossible for me to present anything good next week. Everything I've done can be summarised into 1 sentence 'I tried making virus but I couldn't.'"
So he began to ask me again why is it that I can't present. I told him, I had done some stupid mistakes that had made my transfections impossible to be successful and therefore I had not been able to make any good experiments. He asked me, "Who is helping you on this." I pointed to the other guy, the one sitting there with him, whom is like a post doc himself but is really a technician.
It was a little on the annoying side because other people have canceled lab meeting many times. Am I going to get such a hard time every time I cancel? I mean I am just a grad student I am just learning how to do all this. It is not going to be smooth sailing ever. He was trying to make me feel like I didn't have to push myself but at the same time it sounded/felt like an interrogation.