Welcome to the World of Frogging.
I like to get the top thread to a length I can grab it easily with my fingers (start at the end you ended with)
Then I pull it up, under it will be a loop of thread, snip that carefully and pull on the top thread again...
Repeat, Repeat, Repeat.
Rip it, Rip it, Rip it...
Hence Frogging.
Enjoy the Art!