I didn't say you had a blown head gasket, I said "there's a chance....", and there always is when you've got coolant boiling, etc.
I've told you what I think, and waterpump wasn't the only thing. If this were my car I wouldn't be driving it until I found out exactly what was causing the issues your having, but it's impossible for anyone here to tell you the exact cause just from a description on the forum (sorry, but that's just a fact)
You now say the waterpump was changed, but I would question how it is that you still had 'brown water' in the system if that is the case. Removing the water pump drains most of the colant....but not all of the block. To me this says the system wasn't flushed completely.....and that the job hasn't been done properly.