FSG on it's own is never going to be as thick as normal gels. It will thicken up as it cools down, so try giving it more time.
1/4 C seeds
2 C water
(epsom salt if using)
Place both in a medium pot and bring to a boil. Turn the heat down enough to keep the seeds in a rolling boil, without boiling over. Set the timer for 6 min and stir occasionally. Strain immediately and add any extras that you want.
Using that method, the gel will still be on the thin side, but will thicken up more as it cools and turn into the lovely 'snotty' mixture. I find the thin FSG is nice and easy to distribute through the hair, but that said, I do use a thickener myself.
Don't give up, it's good stuff!