"On the edge of losing the offer" is not losing the offer. The position you're in is not one of failure but catastrophic thinking; besides, even a setback like the one you've described can be surmounted.

Part of growing up is learning how to right the ship when thing go off course. Don't feel like you have to throw it all away. People do care about you, and want to see you succeed. You will succeed, if you're resilient: even if success ultimately looks different to how you imagined it.

Please talk to someone - your university can help, or a GP. There's also lifeline - 131114

All the best. I'm an Australian teacher, if I can help at all DM me.