I left my baby at 7 weeks to sadly go to a funeral, I combination feed so meant I could.
However despite the sad reason I had to leave her the first time, I knew i would be happy to leave her early on as I found the 'mum' adjustment quite hard going and needed 'me' time. She's now almost 5 months and I've left her overnight once for a girls weekend and a few local girls nights plus a few date nights with my DH.
Another reason I wanted to do it early on was that a couple of family members didn't leave their babies until much later on and so found it hard going on both the parents and the baby.
I can't really offer any advice other than make sure you leave him with someone you trust more than anyone, ask them to send you a few pics the first time and stay close by. Mainly for your own sake!
When you return it feels so amazing to see them again and you feel refreshed ☺️
On this comment above...
7 weeks is tiny. If you need tips on getting used to the idea then you aren't ready
7 weeks isn't tiny, newborn is tiny, but there's also nothing wrong taking seem time out at that point too. Whatever you can do and need to do when you're a mum then do it (all inside the law of course haha).
I completely disagree with the second part If you need tips on getting used to the idea then you aren't ready. You are fine!