So, I'm going to loose my job

I'm (M,33) about to go into a performance improvement plan at work. I can just feel it is going to end with me being fired. The problem? Deadlines.

I cant hit deadlines for love nor money. When I realise things are getting delayed, I panic and try to catch up. This leads to forgetting things. Which leads to more delays. Rinse and repeat.

I don't know what I can do anymore. I'm honestly trying my best but that's obviously not good enough.