yeah I 100000% second this. OP, I still barely know what to do (in terms of uni and studying), and taking a gap year seems like a really good option for 3 main reasons:
1 - It gives me plenty of time to figure myself out
2 - It gives me the opportunity to get life experience I otherwise might not get while studying in uni
3 - I can work and save up money (which could be used for uni fees, a car, etc.)
Either way OP, don't put too much pressure on yourself right now. You're still incredibly young and have a really long road ahead of you. Trust me when I say this - your ATAR and getting into uni doesn't matter as much in the long run as you think it does (unless you wanna get into medicine, but even then there are many different pathways). There have been plenty of people who have gotten a 95+ ATAR, but have ended up dropping out of uni because they realized it wasn't what they wanted. Moreover, when you're 21 you can get into a degree through a Matured Aged Entry scheme, where you don't even NEED an ATAR. That's only 3 years away.
Your feelings are perfectly valid (and normal). Depression is horrible and I completely understand that. It's like being in a hole you don't know how/can't get out of. Seeing a therapist is DEFINITELY worth a shot - they'll be able to help guide you to your happy place
I wish you luck bro - I mean that. If you're capable of getting a 90+ ATAR, clearly you've got massive potential and will do amazing at whatever it is you find passion in. Just give it time, and most importantly, have fun.
Wish you the best brother