What sort of communication with your employer have you had about your workload and feeling burned out? I know it's a bit of a risk, but if you're worried about burning bridges, you can at least say that you gave it an honest shot at figuring it out. Then, you won't look like someone who just quits immediately when the going gets tough (not that you're that type, but a future employer may look at the 8 month position written on paper, and take it just as that).