Tess,
You said that you have never had trouble living with uncertainty, but I would argue that if your obsessions were about contamination, you were probably worried about contracting some sort of disease, or being contaminated in some way, right? This is an example of being unable to cope with uncertainty - the sheer possibility, no matter how unlikely, of being contaminated in some way, frightened you so much that would obsess and feel the need to ritualistically perform compulsions to prevent that feared consequence from happening. People without OCD are highly aware that it's POSSIBLE that they may contract an illness or get contaminated at any given time, yet they don't obsess about it. Why? Because they are able to live with this uncertainty.
As for me, I've had OCD since I was 9 years old, mostly centering around repeating neutral images or emotions in my mind. I also had obsessions about my physical appearance in high school and college, but the OCD really exploded 4 years ago after I broke up with my ex-gf. I began to have a form of relationship OCD, and I didn't get better for years until I discovered ERP. At one point I even became suicidal over the fear of either 1) having to live with the anxiety I was feeling or 2) relieving the anxiety by telling my girlfriend what was on my mind (a compulsion), while at the same time risking losing her forever because of the content of my thoughts. The anxiety because so bad that I started having suicidal thoughts, and I ended up giving in to the OCD, hurting her immensely, and almost destroying the relationship. I thought my life was over until I discovered ERP, in which after my first appointment I made more progress than I had made in over a year with my cognitive therapist, who tried to use logic and reassurance to subdue my fears.
I realized that the ERP therapist understood OCD to a much greater extent than the cognitive therapist, and that ERP is a much more effective tool for combating fears and anxiety than cognitive therapy. It continues to keep the OCD at bay every day.
-Mike