Like stated above, go get a large cup of coffee and spend an exhausting amount of time in front of the paper tiger (or the FPT if they'll let you) practicing call outs and procedures. Mentally walk through the steps of the automation. Walk through how you join a LOC inbound when you're in FMS, when you're in HDG, etc. Do all you can to pass.
If you don't, you don't.
And if you don't, maybe airline flying isn't for you. That not necessarily a bad thing. It's easy to be discouraged, but think about it honestly; if you can't pass through this, would you feel comfortable in the real plane with people on board?
Plenty of other options for someone like yourself. You've got to have a good attitude and be able to exploit your network. Much will depend on where you live and what you're willing to put up with. But honestly, just pass this stupid check ride. I believe in you. Do it.