Have you checked the tire pressures? by the wording of your post it looks as though you haven't. Might be worth a check, just for your own safety as tires pressures should be checked at least once a week. I don't know about US tire prices but, over here, I can get four new Pirelli P6000 tires, ideal for my 1997 Carina E SE, for around $360 including fitting, balancing, new valves, balance weights, taxes and old tire disposal costs. Tire change time comes at either three mm tread depth or a puncture, whichever comes first.
Ken.