If parent pays my rent but i buy my food and clothes and car insurance; is that considered supporting myself?

It depends on many factors.  Who provides more than half of a person's support may have to be computed on this IRS Worksheet located on page 16.

IRS Publication 501 Dependents, Standard Deduction, Filing Information, page 20, states:

Total Support 

To figure if you provided more than half of a person's support, you must first determine the total support provided for that person. 

Total support includes amounts spent to provide food, lodging, clothing, education, medical and dental care, recreation, transportation, and similar necessities. 

Generally, the amount of an item of support is the amount of the expense incurred in providing that item. 

For lodging, the amount of support is the fair rental value of the lodging.