How do I deal with the fear of not being able to get a word out at all?

How do I deal with the fear of not being able to get a word out at all? I've been a covert stutterer for as long as I've stuttered (around 2 years). However, I've been trying to desensitize myself to stuttering by talking to more people and forcing myself to not hide my stutter. None of the people I've stuttered in front of really seem to care too much, which was a really nice, reassuring, surprise. However, even when around people I'm really comfortable with, I still avoid *really* scary words. Not out of fear of stuttering, but out of a fear of not being able to get the word out at all. If I end up stuttering around them, that's okay, I'll be fine. I've desensitized myself to the point that I wouldn't care too much. But I'm worried that this will happen: I'll force my self to attempt a really scary word. I'm not able to get it out. It's been a while and I'm pretty anxious at this point. The anxiety makes it harder to get the word out, which means I'm still stuck. More time passes. At this point I'm so anxious, there is no chance in hell that I'll get the word out. I'm now stuck in a position where the person is staring at me, and I'm not able to say the word at all. I can try rewording what I wanted to say, but this won't always work, especially when I'm this anxious. I wouldn't know how to deal with this situation at all, and this fear is making me avoid going for the really scary words. The obvious solution would be to just tell them that I can't get the word out. However, the problem with this is, it would be *extremely* awkward for both of us. The conversation would more or less come to an end, because the person I'm speaking too wouldn't know how to react. I do go to speech therapy, and have been taught a few techniques to help me when I'm blocking, but when I'm this anxious none of it works. It's a self-fulfilling prophecy; I'm afraid the word won't come out, which makes me anxious, which makes it impossible to get the word out.