I use the nettie pot EVERY night of my life with table salt and baking soda , about 1/2 tsp table salt and 1/2 tsp soda and mix it up really well with filtered water. This is the only relief from sinus symptoms that i have found.
I am convinced that a lot of ear problems are related to candida as well. I have been putting a tiny amount of peroxide on my ears and sometimes the salt/soda mix will get in there too ( not advisable, kind of hurts and really hurts if there is already a little peroxide in there).
After the nettie pot I put some in a a small rubber bulb, lay on the bed with head hanging over and make sure some of the solution shoots into the sinus under the eyes and it seems some also gets into the sinus above the eyes.
If I don't do this i have a constant low grade infection which causes me a lot of fatigue. It has the added bonus of killing a lot of the bugs other people are suffering from and I never really get a full blown cold of flu.
I have never experienced what you're describing and I would be sure it's not a heart attack if I were you.