I think my problem with what the OP's cousin posted is that it's the only thing she "said." If she had also written "I know how you feel," "That s**ks," "Sorry to hear that," or something along those lines, and THEN said "count your blessings," at least the OP wouldn't feel, rightly, "dismissed." Her upsettedness (hey, a new word!) would have been acknowledged.
Example: A good friend died earlier this week and it's affected me quite a bit. Now, am I feeling anywhere NEAR the grief his wife, kids, and parents are feeling? Heck no. But if I told someone that I lost a friend and was feeling down, I would hope the first and only words out of their mouth would NOT be: "At least it wasn't YOUR husband."