I do think it is part of the process for most any life altering situation.
I had a very bad experience on Sunday and I am still trying to figure out why. It was a lovely day and I was blowing out my hair. I had plans for the evening and really did not have one thing on my mind other than enjoying myself. All of a sudden out of the clear blue I had an anxiety attack that took my breath away. I had the "feeling" that I used to get when I would pace and go to my ottoman. I felt like my heart was going to blow out of my chest. I have not had an attack like that for a very long time. All the tools I have learned to cope with such a high level of anxiety flew out of my brain.
I was furious with myself. Partly because I had the actual attack after doing so well for so long and partly because I had no clue what triggered the attack.
This anxiety stuck with me for a few days and I felt like I was firmly planted back in "last summer" which was a nightmare.
I am better now (not great but better). This morning I was walking the dog and I started thinking the "other way". Yes, it was very upsetting to have the attack but maybe it would be best to focus on the MONTHS I have gone without an attack. While I have made very solid progress I know I am not "cured".
I guess what I am saying is I know for me, I often have to really try and recognize a balance between being proud of my progress (like you should be proud of your progress) and dealing with the backslides (which we all have despite being very dedicated to the process).