I am stupid, I am stupid, I am stupid.........

You can squeeze the split together and weld it shut. I have a similar split in my HWH that someone had welded years before I got it. However, if you do that, when you get the welded tank back pressurize it with compressed air and then leak-check it with soapy water. I found a tiny tiny leak in my welded tank that the previous owner never bothered to redo (like so many other half-a___d "repairs" he did to the rig).

BTW you're not stupid, stupid, stupid... but rather careless, careless, careless... Big difference, there no fixing stupid!