|You could try joining a fandom, too.|
This is complicated by the fact that my fatigue/pain/unpredictable invisible illness make me kind of flaky. Sometimes really flaky. Like, who actually looks at the forecast before making plans, because if a low pressure system comes in they won't feel like doing it? Well, some of us have to. Rain doesn't just mean switching to indoor activities for me, it means there's a chance I won't feel up to doing ANYTHING other than a no pants no dance party on top of my electric blanket. It is a very real part of my life.
That's really, really, really hard for people without endurance problems to understand. And I have found on many occasions there are people who initially think they can deal with the random bail outs, the preferred text sessions to hang outs, the annoyingly illness centered conversation. But a lot of those people, understandably so, can only handle so much. And then they start to fade away.
In my opinion, that shouldn't reflect on you. Don't get me wrong, whenever it happens to me I become a despondent loon because I'm just sure this is a sign that I am not really sick, otherwise, wouldn't people stay and be there for me? (There's also that snag of your personality also playing a part in whether people can't stand you. If that is why they start pulling away, I have no absolution for you. Don't be a dick.) But on the whole, you have to realize that what you consider normal ("They only had to draw 2 vials of blood today instead of 5!") is depressing and a downer for most other people. It saps their energy in a way that you probably have become blind to, because, like all the shirts at Hot Topic say, normal is relative.
I have no advise on how to fix this. You can limit how much you talk about your health with people, but then you don't really have a two way friendship, do you? I think the best I can tell you is to be guarded with yourself, don't take it personally if what you consider a discussion of your current day is too much like whining for someone.
And again, if you have the personality of a dick, then maybe check yo' self before you wreck yo' self.