I think that you've now got both your age and the length of your proposed. Is working against you, too.
Most quotes are for 30days and the cost rises quite a bit for more.
Years ago I spent 10weeks in Thailand, having declared breast cancer and other stuff. Back then it was with Norwich Union which then became Aviva and it's been Aviva I've used since. LIke you, my family live in the USA, and the policy is for worldwide travel.
So shop around, OP, and even (shock, but it can be cheaper!) to stay your 30 days, come back, and go again!
Or ask your family for a contribution, can't see anything wrong with that.
You've been cushioned with free insurance through your bank, but for those of us who've never had it, we've taken the hit from the go-get.
So, it depends how much you want to go, if you can afford it, shop around. and take it from there?
Good luck! I'm sure you'll get there.
Ps, you said you've visited a couple of times a year in the past. Did you sign up to the carrier's frequent fliers programme? My last flights, return LHR- RDU with AA cost....nothing!