Start by deleting that crap, then run $ vimtutor until you are comfortable, read :help carefully, try your hands on simple tasks first then augment the complexi

Start by deleting that crap, then run $ vimtutor until you are comfortable, read :help carefully, try your hands on simple tasks first then augment the complexity… after a couple of months you'll be as productive as before or more and, maybe, ready to do the actual switch. In the mean time, keep using ST on your projects.