Re: Hello, I am david
Welcome to aikido, Dave!
I second Demetrio's recommendation re: PTSD. It may seem like it's overly dramatizing things or maybe being a little self-indulgent, or like "hey, it's over and I'm fine, so no problem, right?" Think of it like any trauma: promptly and properly tended, it may be fine, but neglected, it will likely turn out to be a much bigger problem. Deal with it now, using the services of an appropriate professional.
Re: aikido and self-defense, aikido is great, but it isn't a quick path to mugger-proofing yourself. I'd suggest supplementing it by developing other skills such as situational awareness. I've never had to use aikido for self-defense, but situational awareness has gotten me/kept me out of problem situations many times. Aikido's the backup, so far my primary hasn't failed.