my thermostat has been replaced twice and now is overheating after about 6 weeks of the new one
I’ll assume the overheating preceded the new thermostat . . . ?
Assuming the new thermostat is working correctly, you may have a much more serious problem
Is your coolant level correct?
Good accessory drive belt tension?
No obvious coolant leaks?
Are your electric fans . . . I’m assuming you have 2 . . . both working?
If you are not in a position to check these things, then you’d be better off taking the car in to a reputable shop for a proper diagnosis and repair