Hello and happy new year!
Oh yes I believe everyone who has had insomnia has up and down moments during their recovery. So your situation is not uncommon. More so because you are a mum to a new born. So sleep disruption is extremely common! The fact that you are able to sleep 6-8 hours is a testament your sleep system is working perfectly fine. So what’s there to worry about? Just remember the opportunity to sleep is always there so why keep dwelling on the past?
As a new parent, I think grabbing whatever sleep you can is probably sensible while doing the best to care for your baby. Forget about the numbers! It is when you are chasing numbers or trying to force sleep at certain hours of the night that you run into trouble. Insomnia is really not about lack of sleep or about sleep at all. It is really an irrational fear of wakefulness. But come to think of it, you must have had plenty of instances when you slept very little but was still able to function, almost completely oblivious to how little you slept. These get conveniently forgotten now when you are too caught up with the perceived effects of insufficient sleep.
Please take it one step at a time and get comfortable with wakefulness at any time and any night. Slowly but surely, you will become indifferent to it and your sleep will improve. Don’t keep trying to escape sleeplessness, embrace it and use the time fruitfully. Good luck to you.