Sure, you can drive it for a while. The squealing sound is produced by brake dust getting rubbed against the rotor when you apply breaks. The brake pads that you have on now have caused grooving on the rotors after these many miles of use. Break dust, which is extremely fine and very hazardous, if inhaled, is now settling in those groves. When you apply breaks, the brake pads rub this dust against the rotors causing this awful squealing noise. Brake dust is the worn out by product of brake pads. Make sure that you get the rotors resurfaced when you go for service. Your service shop should check the thickness of the rotors before resurfacing them. If they are too ground down, replace them. Otherwise they will not be able to dissipate heat properly and would warp.
As I mentioned earlier, you can drive the car safely for a while. As long as your breaks are not making GRINDING noise, you will be fine. That DOES NOT mean that you can keep driving it for weeks. Just days. Get it serviced at your earliest convince.