How do I assure myself tonight that tomorrow I will do the things I want/need to do and not procrastinate my day away for the umpteenth time?
You can't assure yourself the night before, unless you uber motivate yourself before going to sleep in order to wake up early. You have to actually start it the night before or you never will. This is a "do what i say, don't do what i do" deal cuz i failed hard like 2 to 3 weeks ago.
Just do it one day at a time
make a list of things you want to do
do and cross out at least one of the things daily until the list is done
pro-tip: the list is never done