"Durch den Wind sein" in English

Solution 1:

The German expression durch den Wind sein (lit., be through the wind) derives from the sailing term durch den Wind wenden, ‘tack into the wind’, that is, to maneuver at an angle to maintain motion against the wind. Depending on the size of the ship and wind speed, this can be a quite exhausting task.

In the common German expression action becomes a state with connotations of physical exhaustion and a concomitant mental distraction or lack of focus. Those who have no idea of the origin of the expression might think of walking against a strong wind or wind scattering leaves or small bits of trash. Others will use the expression without any thought of metaphor as simply another way of describing a mental or physical state, i.e., a dead metaphor that has become just another vocabulary item.

While this precise sailing technique has not become a common expression in English, two closely allied sailing terms have certainly done so: sailing against the wind and sailing too close to the wind.

Sailing against the wind encompasses the entire action of laboriously tacking back and forth instead of moving in a straight line. This has come to mean holding a minority opinion against the “wind” of the majority:

Mitchell then joined with several other towns in the effort to have the capital remain undisturbed, but soon found they were sailing against the wind. — Bismarck Weekly Tribune (Dakota Terr.) 6 June 1884.

Several towns in the Dakota Territory opposed moving the capital to Bismarck, which the majority of the territory favored.

Sailing too close to the wind is not tacking soon enough so that forward motion stops or, depending on wind speed and the size of the craft, the boat capsizes. This has come to mean engaging in risky behavior:

The important reductions of the tariff under the Clay compromise were not to take place until the next year. The treasury was sailing too close to the wind for the nation’s financial safety and it became necessary to enact a law that would prevent these reductions going into effect. — Los Angeles Herald, 6 Apr. 1909.

English sailing metaphors, then, can’t carry the same meaning as the German because they are already occupied.

So in the German expression, you have a sharp turn or a back and forth motion on water that leaves a person exhausted and disoriented. Transfer that to land and a vertical plane and you get:

I’ve been on a real rollercoaster. / It’s been a real rollercoaster.

This can imply experiencing a wide range of emotions, which isn’t at the forefront of the German expression, as well as hectic activity, which often is, and both of these can be exhausting. At the moment, however, I can’t think of another metaphor that keeps both the physical and mental states of durch den Wind in one place while still maintaining the action underlying it.

Solution 2:

You suggested possibly the most common terms

I'm sorry I didn't call you, I've been a little distracted lately and forgot.
I'm sorry I didn't call you, I've been a little traumatized lately and forgot.

However to be more vague as to an important reason :-)

I'm sorry I didn't call you, I've been a little preoccupied lately and forgot.

preoccupied [adjective] Engrossed in thought; distracted. https://en.oxforddictionaries.com/definition/preoccupied

or looking for the closest to being blown about by the wind

I'm sorry I didn't call you, I've been a little blown apart lately and forgot.

However it would be more common to say one of these two related to fluttering about

I'm sorry I didn't call you, I've been a little flustered lately and forgot.

in a state of agitated confusion https://www.merriam-webster.com/dictionary/flustered

I'm sorry I didn't call you, I've been a little perturbed lately and forgot.

to be worried or upset https://www.merriam-webster.com/dictionary/perturbed