Hi all, I'm not a big poster here but I'm struggling tonight

not even sure what I want to ask or if I want advice so I guess it is more of a vent.
So basically, I've suffered with anxiety for my whole life as long as I can remember. But due to it being belittled and brushed off from childhood by my father and my ex partner (I lived with my father til age 16 then my ex from 16-27), I honestly never really recognised my feelings as anxiety until around 5 years ago (I'm 32 now). My whole life, all I've been told is "just don't worry, you're fine, don't be silly, don't be daft, you're being ridiculous". About EVERYTHING. And my father always made me feel like everything I do has to be PERFECT and asking for help is a weakness. For example, as a kid, I couldn't ask him to help with spelling, he'd tell me that I know where the dictionary is. So I've always been scared to ask for help, or felt like I shouldn't ask for help because I should be able to do everything myself.
On top of all this, I also had a miscarriage last month which really shook me, plus a scan found other health issues in that area which will require surgery. My mind is going crazy every single day after this past month, as well as general Covid life affecting everything for the past year.
I've been off sick from work for 3 weeks and am due to go back tomorrow and I'm shitting myself. My work think very highly of me, not trying to toot my horn, but I know my manager likes me and thinks I'm a good worker (I'm an admin in a university clinical trials unit).
But I know that in the past couple of months, my performance has slipped a bit and I'm so scared I may have forgotten to do things or left a job too long by putting it off, and scared I'll get some sort of disciplinary tomorrow or something. I'm not sure anxiety is a reason to explain poor performance and slipping up.. it seems like a daft excuse and not good enough.