how do I get rid of block anticipation?

how do I get rid of block anticipation? Hello, when I'm alone I don't block but infront of people I do and the main reason is anticipation. I struggle with words that have vowels as the first letter like "eight" and I know this is just in my head that I stutter with these but I'm always stressed out when I have to say them in class and just end up saying 'I don't know". This is one of the main reasons I stutter so I need some advice on anticipation.