Please help

I have a dentist appointment later today but I’ve convinced myself I probably have salivary gland cancer and am freaking out.

The reason I’m going to the dentist is because I’ve had a cracked molar for over a year and now I have a hard lump underneath my jawline where the submandibular gland is.

Currently in no pain, but tooth has bothered me off and on for over a year. I am hoping it’s just an infection but why the hard lump? Is it a swollen lymph node? Infected salivary gland? Or a tumor?

What is the likelihood of it being cancer? I used to smoke but don’t anymore. Otherwise have great oral hygiene, aside from cracked molar. Despite having white teeth, brushing and flossing regularly, I have frequent cavities. Severe dental anxiety is why I haven’t taken care of this sooner.

The lump is hard, maybe the size of a large bean. I’m so worried