Screen sharing without allowing others to access my account?
Yes - the Apple Remote Desktop app allows you to curtain the controlled computer to lock out anyone that's physically at the computer while you work remotely.

You could also set your work Mac to boot to a harmless account that auto logs in and is not an administrator. When you use OS X screen sharing (as opposed to Remote Desktop) it will ask you if you want to share screen with the "dummy" user and you can decline and start your own session that isn't visible locally.

Try the second unless you want to invest in the Remote Desktop tool or can't add a second user due to work constraints.