The design has multiple problems. First of all, you say it was working fine. I can't believe that. That bridge cannot be switched by a PIC. Your input voltage swing has to swing from zero to 12V to drive the bridge.
What is the purpose of T1?
What are the part numbers of your MOSFETs? When you post a schematic here, you need to include the values of all components.
What is your PIC supply voltage?
Let's deal with these first, then we'll get on to other issues.