Turn on tap click, this will get you back up and running at least. It should let you tap the touchpad to do the click function.
1.Go to the Apple menu and open “System Preferences”
2.Choose “Trackpad” and go to the “Point & Click” tab
3.Check the box next to ‘Tap to click’
You probably need a new trackpad. Cheap and easy fix for someone who repairs Mac's. I just did one the other day. Or do it yourself using a guide on iFixit or similar site.