Your Blurt value changed because the price of Blurt changed.
And yes, there is a large transaction fee for dealing with BTC in and out of Ionomy. My suggestion is getting an easier crypto to take out (cheaper transaction fees like Doge, Hive, Steem, Etc) and trade for BTC later.
So BLURT -> BTC -> HIVE or something? HIVE will cost less to take out?
If so, I will try that. Thank you :)