If it’s more likely that you have someone leaching your WIFI than hacking you (unless you are a target of interest).
If you really are worried about this then backup everything you need and format and re-install the OS. It’s the only way to be sure any breech from software has gone.
Otherwise update your firewall and AV and run full scans including looking for rootkits. Set everything to ‘Paranoid’ mode and lock down your routers firewall as well.
In the meantime also go to a computer you trust and change any passwords for accounts and settings that you think may have been compromised.
Oh and turn off remote assistance again.
P.S check exceptions to your firewalls and make sure there aren’t any there you didn’t create or allow.
Also where is this computer, Is it at home or at a business also do you have it hooked up through a switch this could help as well.