Sounds like you have post natal anxiety....I did too.I loved being a mum and was certainly not depressed, but second guessed everything, expected myself and everyone else to be 100% perfect in our care of DD1, and was paranoid of making a wrong decision/forgetting something meaning harm would come to my baby.
I don't think the events around that time helped....Grenfell disaster and terrorist attacks, then a local little boy died of meningitis, all of which scared me alot.
I had the intrusive thoughts aswell....an example being when we went on holiday I was worried about leaving the steriliser filled with water in the hotel room incase the cleaner secretly laced it with bleach.
It feels crazy looking back but at the time it felt very real.
It didn't help that DH also has anxiety/OCD and leaned on me alot to make decisions, take the lead with DD which felt overwhelming.
When she was a 1yo I got CBT which helped me learn to let go and not beat myself up or panic about every little mistake or risk.
As she grew up I gradually became more confident and less anxious...I'm still definitely what I would describe as a protective parent, but in a reasonable way not a paranoid unreasonable one.
We now have DD2 and the experience has been very different, we have both been sooo much more laid back this time around!
Hope you manage to get some help like I did, and things feel easier soon.xx