Yes, I've had this issue myself. It happens with cell phones too. More often than not, you should powercycle your router and let it reconnect to your modem. Routers for some reason go funky when it comes to maintaining client connections sometimes. Simply turning it of and on won't help.
What you'll want to do is turn off both modem and router. Wait 1-2 minutes. Turn the modem on, let it establish a connection or rather go "steady green," plug in or turn on the router, let it achieve connection, and restart your affected devices. It's worth noting that you may have to reboot the router through its internal page if it can't establish a proper connection with your modem.