I saw your thread title from the main forum board and had to read it, because I have that issue too. When I read your post, I though, Good Lord, I have the SAME problem.

I am DXed with bipolar, not PTSD, though. My bipolar does not cause me to fret (for days, not just the night before) about appointments, meetings or even lunch with a best friend I am super comfortable with. It's anxiety, and whatever DX or issue it is born from, it's still anxiety and like you said, you need help with it.

What you also said about the sleep is dead on. I wish everyone understood the importance of sleep. If this anxiety is isolated to the night before, is there a way to ramp up your bedtime routine? I mean, like to the max. Ex.: you have an appointment tomorrow and anticipate not sleeping tonight. Go on the offensive. Start about 5:30 or so (or as early as possible). Start winding up the day. Dinner and dishes done, homework or chores complete (you or kids). Focus on things that are quiet, relaxing, soothing. Really focus on your warm bubble bath (or shower) with lavender scents. Take it slow. Relaxing. Focus on making a perfect cup of Sleepytime tea, or great hot cocoa. My tdoc told me about a drink the Europeans use at night time- it might sound terrible but it's amazing. Warm milk with vanilla and sugar. Slowly drink a big mug of it and enjoy. You have to tune your brain into the soothing, relaxing bedtime things you are doing at the moment and STAY IN THE MOMENT, until you're ready to just pass out.

Early in the evening, be sure to completely prepare for your appointment as a way to address the anxiety and basically put it away. Your car keys, purse, checkbook or credit cards, any forms or journals you need to take with you should all be together if possible. Personally, I also have to have written a list of sort of things I want to address with my tdoc, but that's probably just me and my neurosis and tendency to wander from the topic. Anyway! Make a point to do this, make it an honest, obvious step in your mind- and be done with it for the night. "Put it to bed."

I hope something I suggested can help. If not, I can honestly say I know what you're going through and still fight it myself. Good luck.