Anxious!

So my period has been all out of whack the past few months. Aug I had my period for 3 weeks straight, Sept I had it for 12 days straight, and October I was 11 days late and swore I was pregnant- kept driving myself nuts taking preg tests every other day- then got my period for 12 days again! Oct 11 was the first day of my last period- today is Nov 23 and nothing yet. I swore I wouldn't keep taking tests and getting excited just to be let down (was really taking a toll on me emotionally) so I haven't taken a test. I have an appt with my OB on Dec 1 so I'm trying to wait patiently but I fear that one day I'm going to wake up and my period will be there :( . I should add that I have 4 yr old identical twins and 3 home pregnancy tests said neg. so I'm trying to be patient and wait for dec 1. Any words of encouragement? I feel like I'm pregnant but I felt like it last month too n then the dreaded "visitor" came.