I know nothing about HR issues and stuff, but I don’t think they can count the first meeting/discussion as a warning if it wasn’t documented. It’s just your word against theirs for heaven’s sake! Any discussions about performance should be documented on your personnel file.

What are your team saying you’ve done/complained about? Are your new targets/actions achievable or not? If not then it sounds like your manager might just want you out.

If I was you Apple I’d re-do my CV for temping jobs, particularly highlighting all your 'temp worthy' skills, and get it out to agencies asap.

Have a chat with a few of them and find out a) how quickly they would be able to get you work and b) how much you’d be likely to earn. If it’s enough to cover what you need financially I’d hand in your notice. Are you on a months notice?