Dang why am I just finding this thread, oh well, assuming you mix your honey into the water thoroughly, your gravity is extremely high due to berries replacing some water volume. What I would do if you aren't going to ferment in a wide mouth or bucket, draw out half of the liquid volume into a gallon jug. Airlock that jug or keep the cap loose enough for air to flow out, then put it in the fridge or ferment it side by side your 3 gallon. Measure gravity in the gallon to double check the fruit isn't misleading your hydrometer, if it's still above 1.120 go ahead and add water to the top of the shoulder on the carboy. Stay on top of you nutrients, 71b consistently gets stressed in this environment but will produce delicious melomel. As soon as you even think you detect a rotten egg odor add some nutrients, trust me on this one, and heads up degassing is going to be rough the first few days. Going to overflow if you aren't to careful.
I really need to get my recipe up here lol, not telling you how you have to do things here, just offering experience cus I've made these same mistakes and had to learn the hard way. Wish you the best of luck and don't worry, you learn alot with your first mead. Cheers.