"Too much memory" is pretty relative.
Agree with others re: relax, all is well.
Add: FreeMemory Pro might actually be a detriment to system performance, since you might be forcing the system to do paging, and probably gets reloaded and kept in RAM, flush again, page again, rinse, repeat. Not as big an issue on SSD, but with an HDD, noticeable and drain on battery.
As a quick test, pulled up Safari, Chrome (64-bit beta), and Firefox. All three displaying the same three webpages. Total memory usage:
- Firefox: 371MB
- Safari: 481MB
- Chrome: 492MB
Safari, I can see, since that's my primary browser (95%+), so not only displaying pages, but also has the vast majority of cookies, history, reading list, , extensions, bookmarks, etc. Chrome gets the next most usage, but only for Facebook, Google accounts, and streaming TuneIn Radio (so, not a lot of extra crud there). Firefox, I go in once, maybe twice a week to visit one specific website, maybe use it if other browsers are giving me grief with a specific website (rare).