Hello,
It sounds like you have an unstable connection to the game server (which is not the same thing has having a poor internet connection; one can have good internet but a poor connection to the game server).

Please try these steps (in this order and don't skip any), it may resolve your issue:

1) Clear the Client Cache

2) Flush your DNS Cache

3) Reboot the PC (To be extra sure, reboot the Modem/Router too)

If your problem persists, there are only a few options left:

1) Trying some VPN programs (try all of the VPN servers each one offers to find one that works best for you)

2) Waiting a while for it to resolve/settle down

3) Contacting your ISP for assistanceHopefully the first set of steps will resolve the issue for you. If not, a VPN clears up the issue for most players.
4) Attempt a clean reinstall of the client in case your files became corrupted.

Thanks and have a great day!