We are desperate and ready to quit parenthood lol.

Ok, so we just returned from visiting relos in Europe. Our DD (7 months) adjusted to the new time zone over there within two days. Super proud of her. We spent 4 weeks over there and she stuck to her normal adjusted sleep routine the whole time. We just arrived back in Australia on Sunday. Ever since she has not slept properly at night. The first night she was up every hour. The next night she was up every hour until midnight, then wide awake until 4am, then waking every hour again. It's Friday morning (3am) now and she is still awake with hubby trying desperately to get her to sleep. We are exhausted. Dh had to call in sick today, as we cannot function anymore. This is ridiculous. We both only slept an average of 3 hours broken sleep every night . What can we do to get her to sleep at night again? She's just not tired. We get her to sleep and she wakes up 10min later wide eyed ready to play. She gets tired around 4am or 5am and then wants to sleep all day. Which was fine at the beginning, but DH has to work and I can't cope with her alone all night. So far we've tried letting her call the shots and sleep when tired (biiig mistake), we've tried sticking to her normal routine and wake her after the normal sleep time after her naps (she normally sleeps around 40-90min depending on her tiredness, with no more than 2 hours awake time in between). But this also didn't work. She's still awake at night. So we got desperate and tried keeping her up for 3 hours at a time with 60min sleeps in between to get her really tired by the evening. Still no luck. She goes to sleep, and then wakes up every hour until midnight and then whinges until 3am before sleeping only short intervals again. We tried putting her to bed earlier, later, normal time. Nothing works. We are beyond exhausted. She used to sleep 7.30pm to 6am, have some boobies and then sleep til 8am. She was a dream sleeper. Now everything is ruined and I just want to die. I know we should be sticking to one method rather than trying a new one every second night. But which one is right? What if we pick the wrong one and make it worse? Btw we don't do cc or cio, because she gets into hysterics after only 2 minutes and cries so hard she can't breath anymore. I was never a fan anyway, but even when really desperate this method wouldn't work. Also we live in a unit with our neighbour's bedroom right next to ours and they can hear everything. They already hate us and complain all the time. So I can't have her screaming all night.

So. What do I do? I need my sleeping baby back. Even if she woke every two hours to feed and then goes back to sleep, that would be fine. I just can't take the screaming and not going back to sleep when she wakes a night. ...

Help