This is entirely why I have spreadsheets and lists (I am not even joking!).
Out of the 7 towns that I am currently running, they are all massively WIP's and there is so much to do it is massively overwhelming. So I actually write things down and make myself stick to one thing.
Honestly, I love nothing more than having a project, but it can be overwhelming if you are trying to envision all of the things at once. Start with one thing... paths for example. Then trees, then bushes, then flowers etc. It gives you a focus and makes the game so much more enjoyable

I love my unfinished towns, because I can see the little bits of progress each time I load up
It's supposed to be fun, so if you aren't enjoying it, maybe try taking the pressure off a little and just enjoying your villagers, or spend some time on the island playing games