I'm sorry you have lost posts - especially thoughtful ones. The forum software resets your connection after about 30 minutes of inactivity. This is a security thing so that a member won't leave their login open and unattended (hacker prevention) and to ensure that those on mobile connections and thin data lines won't run up unanticipated data use. It's worth noting that some internet providers do the same thing so you might check your settings...
Typing a response is a period of inactivity as far as the server is concerned because you aren't refreshing pages, navigating around the site, etc. Some suggestions:
1. Depending on your browser if you hit submit and your post is lost, use the back arrow on your browser to return to the last screen - it should recover your post text and then you can copy/paste.
2. Copy your post before you hit submit. The fastest way is to highlight all text and hit ctrl and C on your keyboard. This will copy your text to your clipboard and then on the off chance that your post is lost you can paste it into a new reply window and repost.