Is it 3/4 time??

In the last two weeks I have a total of 59.25 hours and still have 2 days with 7.25 hours to go on this pay period. I know that my manager is 3/4th time with benefits and insurance. She gets 29 hours a week and I get about 25 or sometimes up to 29 as well. I will be well over 60 hours this coming Tuesday. I am the only one of my coworkers that ever works lately besides my manager and she is a different position than me. I have 2 coworkers that don't work more than about 9 hours a week and I'm the rest. They don't even have anyone that will cover me if something happens or I need to call in. I've had to come in really sick before because no one will cover and my manager doesn't answer me. But am I close enough that I should push harder for 3/4th or full time since I am the only one that works lately anyway. I make $8 an hour.