Thanks, wickedwings and Alex. I appreciate that you've given me things to think about.
For the record, I have a relatively rare blood clotting disorder. There are a variety of clotting disorders, and I've been found to have a genetic mutation that predisposes me to clots, but this particular disorder is a leftover from my near-total bone marrow failure in 2005/06. One doesn't usually get it without having had some other medical issue to kick it off.
Like I said, I take my pills and I'm largely fine, with intermittent minor problems. The other folks on that forum continue to have clots and worse even while on the medication that is supposed to prevent clotting. Usually they have other disorders as well, such as lupus (which can coexist with this but doesn't necessarily come along with it). Many of them have family members with equally bad problems with the disorder, as it can run in families.
My family's fine, I'm fine, and it just makes me feel bad to read of all the horrible things going on when I'm fine.

I feel guilty, and then I don't know what to say, and then I want to run. I think I'm going to take Rayna's advice and just quit reading stuff online!