It sounds like an Ascaris worm! But there is another type of worm that infects fish as well-- alot of Norwegian fisherman get infected with it when they eat raw fish. I forgot the name of it already, but it coils up inside the fish and is hard to detect unless you are looking for it. It's clear to opaque in color also and you do start to feel alot of digestive irritability within days after being infected.
Probably the boiling temperature killed any possible eggs before any got into your body.
To be on the safe side, you may want to purchase some Clove Oil, or good quality Cloves (which you can purchase online if not sold in your area.
I'd take Take a teaspoon of clove oil or tablespoon of cloves three times a day for 1-2 weeks to kill any possible larvea or live eggs if you are concerned.
Good thing that you cleaned the fish thoroughly before eating it too.