Currently in a similar situation. Been at a place for ~4 years. At first there was people there to connect with but now the company is dieing, people are leaving in droves and the owners should have retired 20 years ago.

After a lot of thought (i.e. stick it out tell the company is bought or move on) I decided to move on.

So currently I reduced my hours to part time and started to focus on my own budding web consulting buissness while also applying to companies I feel OK supporting. (Personally my main goal is to not have a boss besides my clients but thats gonna take time.)

Tl;dr: if your not feeling it move on. Listen to your gut.