I had a Velvet/Oodinium attack - also after I stopped using my QT
tank. I too was new and excited and moved too fast. Water quality fluctuated badly and I didn't diagnose the problem early enuf. Killed 8 fish. everything from a bristletooth tang, dottybacks, clowns, a Scotts Wrasse, & a blenny. A yellow tang, watchman goby, and a b/g chromis survived.
I used a product called Revive twice within 8 days. My shrimp, starfish, and corals did fine thru it too. After 2 weeks without removing the remaining fish, I began adding fish SLOWLY and after QTing them only. Everything has been fine for the last 5 months. Maybe I was lucky, but the Revive did seem to work for me. I keep it on hand now since it's supposed to used right away.
Good luck. I learned valuable lessons thru the pain. Sounds like you have too.