It might be a challenge, but I suspect you can do it. First, call the Philippines embassy in Doha and ask what the requirements are to get police clearance. You first need police clearance in your own country, then you can apply for it in Doha.

If you are really lucky, you still are in contact with the mandoub of your old company and he can do it for you. If not, once you know the process from the Philippines embassy, ask an old friend to take care of it for you. I think you'll need someone in Doha to help you move the paperwork around. If you don't know anyone here still, I suspect you can post a message on QL and someone here can offer the assistance.

Good luck!