Song Help Request Nostalgia by Alice Phoebe Lou

If you haven't heard of Alice Phoebe Lou, she's amazing and you should check her out right now. This post is specifically about her song Nostalgia. Here is a video of my favorite version:

https://www.youtube.com/watch?v=U3ERNZPDrFU

Been playing this on the uke for a while, but thought I'd share my arrangement. So far, I've been able to work out a chord progression of:
A7 Gb7 D6 E7

But, there is one chord that comes before the E7 and walks down to the E7 that I know how to play, but I don't know what it's called. I don't have a formal music education, so I'm not sure how to go about constructing/deconstructing chords yet. Can someone help me out? The chord diagram is below:



Any help and tips for how to figure this stuff out on my own would be great. Thanks!

-Wes

I use GuitarToolkit app for help like this. It's best recommendation is E13. The note are G# D E C# , so,you have E root, G# third, C# sixth, and D seventh, so E13 seems fine to me (even though it's missing the fifth, ninth, and eleventh notes) since you are headed towards E7. With only four notes, ukulele chord naming can be rather "esoteric" and inexact at times.