Feel sick with health anxiety

I'm in my late 20s. My mum was diagnosed with exon 19 deletion lung cancer last year in her early 50s and I'm told it's not hereditary. But several of my other family members have been diagnosed with cancer young, all different types (before aged 60). I found a breast lump a couple years ago and never got it examined as they told me to call if it got bigger which it didn't. Now I've had a cough for 6 weeks and am catastrophising thinking I have breast cancer and it's progressed to lung cancer or something.

I called my dr and he's requested a family tree to forward to genetic testing drs who will decide if I should get genetic testing. I'm also getting the breast lump examined.

Because of my family history of cancer, I always think I've got cancer (I've been for a check-up for 2 things before), and when my mum got it so young and for such a rare type (literally 0.003% chance!?), I have just spiralled, yet it didn't kick me into action to get the lump checked and I feel like an idiot.

I have a young child and I'm a total mess panicking that I've messed up. Deep down I don't think it is anything (I had an 8 week cough last year that went after antibiotics). I think I need to get a therapist. Has anyone been in any sort of similar situation before and got any advice please?