Can I say I paid for more than half of my living expenses?

Exactly when did you move back home? Did you pay your friend rent?  Are you paying your parents for rent, utilities, food, etc? (Those are all considered Living Expenses).

@SweetieJean I moved back in June. I paid rent with my friend at the house we rented. I pay for my car and phone, but no rent, food, utilities.

Simple answer: no.  From  what you  described you did not pay for more than half your support in 2020.

But you didn't provide any amounts.  So, for a definitive answer, you need to do the calculations.  

The IRS has a worksheet that can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf The support value of a home is the fair market rental value, divided by the number of occupants.

Here's a wrinkle, using an example: you friend pays $1000 per month rent, but you only contributed $300. There was just the two of you.  Your friend effectively provide you $200/Mo of support that goes into the calculation.

In that case, you did not pay more than 50% of your living expenses for the entire year.