Good for you! I had a professional organizer help me with my office (piled with paper!) and my work flow once, and it was well worth it.
Two things I learned from that experience:
it is good to have an outside party who will question your choices and help you prioritize; and,
it is great to have someone alongside you as you plow through your stuff -- someone to talk to -- someone to haul away trash bags -- someone to keep your energy up.
When I retired from that job and REALLY had to clean out my office, I always had one of our teenage volunteers in there with me, just to keep me company and haul away trash bags and label/tape boxes. It made the work go more quickly and was lots more enjoyable.