My mac got hacked Help~~!!

What Mac, with what version of OS X?

Ayup, looks like somebody has screen-sharing access — probably something (compromised) that was installed onto your Mac (downloads from sites other than the Mac App Store, and cracked apps from torrents are notorious for this), or somebody has your credentials.

Whoever did this also has access past any network firewalls, which usually means that there's dreck installed on your Mac.

Etrecheck might find the more obvious stuff (post the report here, if you want us to look) and maybe an add-on scan tool — the awfully-named malwarebytes tool gets recommended around here, though I've not used it — might find and clean up the dreck

In general, get a complete backup or two of your disk, prepare an OS X installation (either via Internet Recovery or via a locally-built USB installer), wipe the disk, reinstall OS X from Apple download (and OS X downloaded via another computer, preferably), and change all your passwords on your local system, mail servers and web sites elsewhere. When you recover, ownload applications only from the canonical source, and recover your files from pre-breach backups — do not copy applications over from your backups, and only copy your data files if you have to.

The cleanup is tedious and annoying, but is probably somewhat less of an issue here than the existing exposure of your credentials and data access and the rest — that's already gone, if the attacker was inclined to do so. Watch your credit card reports.