Most people in the northern hemisphere are D deficient... so altho you should take action to fix it, don't let this diagnosis scare you. This deficiency is definitely not isolated to vegans.
If you can afford it, best and preferred way to treat D deficiency is a sunny vacation.
You only need a few minutes in the sun (without sunscreen!) to get your daily dose.
If a vacation is not on the horizon just go with the D2s daily. D3 absorbs better.. so the dose for D2 should just be a bit bigger... which one you take shouldn't matter.
And eat more mushrooms (D fortified if you can find 'em).