Several things to try:
Turn everything off and switch back on in this EXACT order:
Modem - wait at least 30 seconds for the lights to settle
Router - wait for lights to settle
Laptop
This reboots the modem and very often solves the problem you have.
If not:
Disable your firewall temporarily. It may have automatically updated and be shutting you out.
Still no good -
Reset the router to default settings. This cancels any security you have set up, so you will need to do that again. I reset mine my holding down a tiny button for 10 seconds.