A lot of people don't realise that they have chronic illnesses, and become frustrated when they are not cured overnight or at least have sufficent symptom relief in the matter of a few weeks. When it comes to months of little to no improvement or even further progression, people can become agitated, anxious and downright depressed. It's a hard pill to swallow, which is why many people with chronic illnesses go through the five stages of grief (some never reaching the last stage or going through the same two or three stages repeatedly).
Believe it or not, people who have been chronically ill for years- even those chronically ill for most of their life- still get frustrated, just as much as they did in the beginning when they did not improve dramatically with treatments. They too get angry and depressed. Doctors continually dismiss them, despite having a proper diagnosis, just as they would dismiss a person with no diagnosis who's symptoms don't seem "too bad." They are still stressed by doctor appointments, tests and new medicines. And they are tired too.
I'm not going to lie to you and say it always gets easier. Sometimes it does get easier: There's always the possibility of treatments that control symptoms very well and even remission. For others, it doesn't. But in the mean time it's hard. It's so hard that it might make you question why you keep trying. Chronically ill people seem prone to having bad luck as well. That's all it is: You didn't do anything to cause anything. You did nothing wrong. You've got to keep trying and fighting against that bad luck.
Life isn't fair. It's really not for anyone, even though it can certainly seem that life is having a go at you and no one else. It's not going to be easy, I promise you that. I will bet my right hand that you will consider giving up at least once. It's not something to be ashamed of either. Trust me when I tell you that I've considered giving everything up, that a life spent on my couch isn't so bad. But then I remember how much work I've put into life, and how much farther I can go if I keep at it. So I sigh, give my pillow one last hug and try my best. It doesn't really matter if life goes to plan anyway, it just matters if you give it a good try.