I have anxiety whenever I go out to eat in a sit down restaurant with friends... Can anyone relate?? Give advice?

So ask for separate checks. Anxiety solved.

Why the H*ll aren't you asking for separate bills?

Ask upfront for a separate bill. 

You shouldn't be eating in sit down restaurants now anyway, because of the virus.

But to answer your question, you can ask for separate checks (bills) for each person, or you can have them charge your card for 1/3 of the total.

One way to go about it is by "Going Dutch" which according to Wikipedia "indicates that each person participating in a paid activity covers their own expenses, rather than any one person in the group defraying the cost for the entire group. The term stems from restaurant dining etiquette in the Western world, where each person pays for their meal." Extracted from the link below.

Ask for a separate check when you order.  Or you can pay for everyone.   Or if there are four of you, you can put four cards in the thingie and ask the server to split it four ways.

If you're eating anywhere more upscale than a Denny's, it's horribly tacky for everyone to sit at the table counting out their cash, figuring out who owes what, making calculations and changing bills at the table.   You're in a restaurant, not playing Monopoly.   Discretely take care of your own bill/tip or take care of the whole bill/tip or split it evenly and don't worry that someone else's meal cost more.  

See a food therapist.