Help with blocks of vowel sounds.

Help with blocks of vowel sounds. I've stuttered my whole life, and I've grown pretty well adjusted to it, as now I can speak effectively in conversations, with a few stutters here and there. Recently (in the past month to two months), I've been having significantly more trouble with vowel sounds that begin a word. I try to say it, but no sound, not even air comes out. It looks like I have my mouth open and I'm not able to say anything. This is especially bad in Spanish class because I love to learn it and like to speak in class, but there always seems to be a vowel sound that I just can't get out. If anyone has some strategies that have helped them I'd really appreciate you sharing them. Thanks!