There's a general theory out there that everyone who suffers a loss goes through five stages of grief in order to come to terms with what or who has gone.
In fact, many people believe these stages are more applicable to someone facing an illness or disease rather than someone who has actually lost someone.
And I'm starting to understand why.
Because while I always state, very clearly, that I am still 'me' - of course having MS has changed me and coming to terms with 'Catherine who has MS' hasn't always been an easy ride. There's no doubt in my mind that I've grieved for the me 'before'.
So, in case you're wondering, the five stages are denial, anger, bargaining, depression, and acceptance.
The stages don't always work in this order and a few theories I've had a quick read at also say that they can pop in and out at different times.
For me, unbelievably, the first stage I encountered was probably the one most people face last, and that's acceptance.
On diagnosis I was very stoic, determined and I suppose this is because I finally had a reason for the previous months (even years) of feeling unwell. Finally I had a name for everything that I thought I was imagining.
But acceptance doesn't mean that I haven't had days of the other four stages.
In fact, I started writing this post some weeks ago when I was going through a 'low' period - I guess that would be the depression stage. And there wasn't anything that triggered it. I simply felt incredibly emotional and teary-eyed. And it was horrible.
Along the way I have also had moments when I've felt the anger bubbling under the surface until I can hold it in no longer, shouting out in pure frustration, 'Why me?'
Because I am bloody angry. I'm angry that no matter how hard I've worked, how much love and care I've shown others, that this blasted illness still choose me.
It's often after an angry moment that the bargaining stage takes over. In my mind I can hear myself saying, 'Maybe they did make a mistake. Maybe if I can just be a better person the MS will disappear.'
But in my heart of hearts I know it's going nowhere. I mean, the NHS wouldn't have me injecting myself with very expensive medication if I didn't have MS now, would it?
Ah, and in creeps the denial - without me even realising it.
If only it were true.