From my personal experience, I've posted 3 things before, hopefully they'll resonate with you:
Transitions/Explains why it is hard to shift to writing the paper, I've had a similar experience.
Make the transition faster using LOAThis helps to concentrate better.
And that I'd offer that you'll have 5x motivation that if you always have in your mind "the end result", which is to have the two papers holding in your hand.
If you are interested in RT_Wolf's advice, then I wrote an entertaining post about "Imagine the worst case fear-causing scenario. Its easier to fight against something concrete. Then, make the fear-causing scenario so much scarier that it just becomes ridiculous and has no effect anymore. " here:
Get over fear