Turn the amp up, take the strings down, play lightly, relax every muscle in your body and breath deeply and regularly. Adopt this style for all songs you play and practise the difficult songs until you can play them with no effort.
Start by playing the numbers slower, at a speed you can manage and speed them up. Get to the point where you can easily play these numbers at a faster speed than you need, then you will be playing them well when you get into the right tempo.
If you can't make any of this work get a few lessons to point you in the right direction.