I think you are meant to be what you want to be. Yep its great to be prapared but sometimes things dont go our way. I am a software engineer and at one point we had a very critical project that went bad and I was put on the spot to explain what went wrong with the project. It was a long morning and I had a very small breakfast. I started tanking and felt the low comming on. I could put words together to explain what happened. I finally told them that I was out of sugar and needed a drink. I walked out of the room went straight to the coke machine and came right back. I slammed a coke and requested 15 minutes. I came back and explained the issues. After that I went to my desk and I was at about 85 with slamming a coke after checking. So I must of hit it real low. So the point of this story it happens to the best of us. If you are at the masters level you have already accomplished a lot more than most healthy people.
take care and keep with your studies