Well, when you mentioned the things that you had quit, it all added up.
The OCD is not uncommon where anxiety is concerned. I've had to manage this for many, many years - at one point, the anxiety, depression, and OCD caused me a temporary condition of agoraphobia. I didn't leave my house for almost 3 years.
SO........this is all good, and the polar opposite partner isn't a "bad" thing. But, our own issues can really cause a strain on our relationships, and I had to learn that through bitter experiences. Even friendships were strained because of my personal issues.
As far as the parasitic thing goes, try to relax through this as I believe that you probably don't have an infestation. This is just residual from getting off of tobacco and the other.
Take one day at a time, and (if necessary) one minute-at-a-time. Accept things as they come and realize that you are just fine and each day is better and better.
Brightest blessings to you.
EDIT ADD: I don't typically type what people "should do" or what they "should take." I offer suggestions from my own experiences. If there is a subject that is out of my realm of practical experience, then I am pretty general in my responses. :-)