Being afraid of anniversaries gives them too much power. Do think about them and process them, let them know you are there and are going on with living your life now. Anniversaries are individual, we create them; some people get hung up on the loss of a particular loved one or leaving a particular place or some unpleasant event like hospital or divorce; it's an individual thing so owning up to your own events and not ignoring them, hoping they won't notice you is the best get-that-mountain-back-into-being-a-molehill advice that I can think of.

I treat a lot of things like I do unpleasant symbols or situations in dreams; you know if the monster is chasing you that you need to turn around and face it and have that conversation; do the same with real events like anniversaries of unpleasant events. They don't really have a hold over you, they can't decide you are not well and should come back, etc., that is literally all in your own head/perspective. It is not a "failure" to be ill or pre-ordained because you are you and "flawed" or any other such; these things happen to everyone.

There's natural post traumatic stress that goes along with stressful events; I had a major car accident (I was not hurt but my car was totalled) and driving by that intersection and seeing the pieces of my taillights by the side of the road, I was terrified my new car would stall. Coming back to the "present" and reminding one's self that one is not in that event NOW, that bad things are not happening NOW and are not likely to happen in that way again (new car is not likely to stall) and doing some deep breathing and think about something I'm going to do tomorrow or next week, whenever, helps me when I get into anxiety mode caused by anniversary material.

When I was in therapy I use to get strangely depressed every Christmas season; I fought it and that seemed to entangle me more. Finally I let my view get broader, I concentrated more on what I wanted to do this year (instead of wondering what had happened in the past), started some new traditions, read some enjoyable books, and thought about the new year coming and what I wanted for it. If you saturate the "market" then there is less for any particular item; the more TV channels you have, the fewer "good" shows there seem to be because there are so many more shows and they have to fill the time with lousy, cheap, programming. It works on bad events too; get busy with a lot of good, new stuff and remind yourself of what you like and what makes you feel good, and the bad stuff assumes less importance.