Are you going online immediately after booting up? It takes a minute or so for all the shields to get up and running in Avast, so perhaps that is why you saw Avast "fix" itself today.
If this happens again, you can try an Avast Repair:
- Go to Control Panel > Add/Remove programs > Avast Antivirus.
- Scroll down and choose Repair function in the pop-up window.
- Reboot.
Let us know if this resolves your problem. Thank you.