Coping with anxiousness post baby

[Mumof1DS]

I have a 4.5 month old. I don't really know how to explain how I feel, but I think I shouldn't feel like this. I'm just wondering whether anyone else had this and if so, how long it took for you to start feeling better, or what coping mechanisms you used.
Please don't get me wrong, I absolutely love my son with all my heart, but I can't stop feeling anxious about... Almost everything?!
I keep imagining that something horrible is going to happen to him. Like when I'm driving, that someone will rear end my car and really hurt him. Or walking through town, that someone will mount the curb and hit his pram. Or that I'll fall holding him. Or any number of other scenarios.
I often take him out in the pram to encourage a nap (4 month sleep regression...) When he's fighting sleep, he generally has a bit of a moan (definitely not a cry, more a whiny moan) as he drops off/fights dropping off. I feel like everyone is staring at me and thinking I'm a terrible parent and that social services will come knocking at my door.
The rational part of me knows that won't happen, but the rational part of me can't overpower the irrational part!
I don't really know what I'm looking for on this thread. I suppose other people's own experiences that this is normal? Or how you dealt with it.
Input gladly welcome thanks everyone.

Yes, I did - constant intrusive thoughts about horrible things happening to the baby. I think you’ve suddenly got this tiny helpless creature that you are entirely responsible for so you’re hyper aware of the dangers. Not sure if it’s normal, but it was difficult for a while and then gradually passed.

I had this for the first few months!! My midwife said she'd find it weird if I didn't think these things and it's just your way of protecting them.
I had anxiety in the past but haven't suffered for years. After the first few months the thought went away. I still get the occasional one.

I just wanted to suggest some coping strategies for you that I did with my therapist for intrusive thoughts. Don't let the thoughts just consume you, challenge them in your mind constantly and also mock them (when you do this repeatedly they lose their power over you if you demean them and aren't afraid of the thoughts anymore) so I'll give you an example.... Brain: that car is going to mount the curb and smash into the pram. You: (conscious mind/self talk) oh really brain? How often do you think that actually happens in life? Thanks for your input but I don't really need stupid thoughts like that, you're just being ludicrous now so jog on. If you do it once it makes no impact, if you do it every single time you have an intrusive thought it works after a few days/week. You need to be aware of each thought and challenge them, don't just let them seep into you as if the thoughts are facts. I hope that helps.