I think losing readers is just something we have to face after you finish a story, and not every person who followed your first one will be around for the next.
My short comic had it's best month in June last year. That was a full 2 months after I had posted any updates on it what so ever. (I think it got some sort of shout out from someone but I never figured it out haha) I started posting extras last december and it's never hit the same amount of pageviews since. Which is completely understandable, extras aren't for everyone.
So honestly the best thing you can do for your new story treat it like it is. It's new, and not a lot of people are aware of it yet. Market it in the right place. Look for lists you can post it in, and join communities that enjoy the type of content you're all about!