Welcome back
I'm so sorry to hear about your dad.
I think the best way to make sure you stay on plan is to figure out exactly why you fell off the wagon, and to figure out exactly what you need to do to make sure it doesn't happen again. I know your dad got sick, and you had no control over it, but you did have control over you and need to remember to worry about yourself before/along with others, even those who mean the most to you. Just think, if you aren't the best you can possibly be, then you are doing the others you love an injustice too