This is long, but can show you the winding road that sleep can take.
First baby. Longer stretches at 3 weeks so by the time she was 7 weeks she'd sleep from 11-6.
So smug, we had a baby that slept through. Go us... Then she hit 4m and it all went to pot. She settled on waking about twice a night until a year. From there she's had periods where she's slept through, and periods where she's up twice a night. It's currently about 50-50. She's 7.
Second baby: 2-3 hour stretches turned into the occasional 4-5 week stretch by 6w. It slowly got worse again so by 6m it was hourly wake ups. That lasted until she was 18m, then maybe 2 wake ups a night. She suddenly slept through at 2. Stopped again at 2.5. She's now 4.5 and usually wakes once a night, though sometimes more, and it can be for several hours. She's on medication to help her sleep.
It's a marathon not a sprint basically. Whilst we have unusually bad sleepers, I think most people find it up and down for the first few years. There are periods of better sleep and worse sleep. I know people whose babies solidly slept well from a few weeks, but most wake at night for at least the first year, probably two.
Try to nap in the day if you can - you'll kick yourself for not doing so when you're back at work and it will help. Your body will also start to become accustomed to very little sleep which helps you cope. Oh, and share the nights with you partner. Yes he needs to be safe to work, but you need to be safe to look after baby, so try to share the nights as equally as you can to both get some blocks.