The software updater only installs packages from the stable repositories so all you see are stable updates. Unless you switched explicitly to testing or unstable.
Use pamac to update your system and all will be well. As for when to update, that is a personal preference. However, falling behind more then a month seems to long to me.
For a more detailed answer there is this excellent thread:
Since you are new you cannot yet upload images, but the forum users prefer text anyway.