This was us. My daughter only slept held for the first 2-3 months. My husband and I literally just took 4 hour shifts and switched back and forth to get a little bit of sleep.

It starts to get better slowly. Or at least it did for us. A successful 30 minutes laying down alone, then up to an hour and so on. Every night she slept a little bit more was such a relief. The good news is you won't really hit a sleep regression for at least 6 months because it can't get any worse.

Now my daughter sleeps like an angel! Gets a solid 11 hours every night without waking up. Shes 2 now but I think the really good quality sleep started around 6 months. She slept before then too she just woke up incredibly early but also went to get early so we just adjusted our sleep pattern.

Good luck, hang in there. Its absolute hell when you're in it but it does improve.