Intro from a newbie, and my current challenges

Hi all - I just joined recently and thought I'd introduce myself. I'm an engineer for 10+ years. About 6 years ago I was playing around with canvas and made a tool for my knitting to help me calculate measurements and visualise patterns. Fast forward to now and the site has had two complete rewrites (most recently about 2 months ago!), has over 35k registered users and 1.5k MAU in peak season. I also had someone "borrow" the idea and build their own version which has more like 200k hits a month which I'm definitely not at all bitter about.... They are now my main competitor.

I'm currently building in subscription as I'd like to be able continue working on the project and the only way I can do that is if it pays somehow for my time. I'm living off my life savings to do this so things are pretty tight right now. The competitor already has subscription/freemium so I'm hoping people won't be too surprised when I add it

My biggest challenges/concerns right now are;

• Worrying how my users will react to the introduction of this freemium model
• Working alone. Doing a project entirely solo is the ultimate monoculture - I can't see past the things I'm so used to, or the way I would expect something to work, which can leave me out of touch with the reality of the project
• Staying motivated/focussed! I often get days where I just lose all my mojo and want to throw the whole thing in!
• Trying to just get the f*ing work all done so I can ship this thing and get some cash! (hopefully)
• Staying afloat financially through all of this!

The site is available at chart-minder.com. I'd love your feedback :)
Abby