A young client of mine contacted me because he had just lost his first job out of college--after only eight months.
He had broken into a very difficult field by building strong networks and working LinkedIn. His search was impressive, especially because he had never done one before. Unfortunately, the culture of his new/first employer was, by all descriptions, toxic and dysfunctional. The office was a heavy-drinking one (during and after office hours), and he soon found his position description shifting due to rapid personnel changes. Many employees were terminated, while several left of their own volition. Initially, he was excited by what he was learning--exactly what he had been promised when hired. But, due to the staffing changes, management started to transfer a heavy amount of administrative/office management duties onto him.
As he'd be the first to admit, admin is just not his strength. He's adequate, but not much more. The creative part of his job disappeared gradually, as this clerical aspect grew. He was miserable. Disliked the job, disliked the people in the organization.
My advice was to stick it out as long as possible, hoping the organization would stabilize, and simultaneously to begin building networks outside, in case things didn't change.
Like many before him in this organization, he was terminated. The management wasn't happy with his administrative work, something for which they had not hired him. First job!
I told him that while it felt terrible, he'd probably be way happier in a new position, and if the current statistics held, it would probably happen to him again at least twice more in his career. In other words, not as big a deal as he was feeling at the moment. Also, losing one job is not the end of the world--it’s part of how things have worked in the last 30 years, at least.
On one level, he was relieved he no longer had to continue working in a job he hated. At the same time, he was stressed about needing to go back onto the job market again.
He immediately began to worry about how he was going to explain himself, and developed a strategy to tell everyone he met on the search what had happened--that it hadn't been his fault, that it had been a bad circumstance.
No! Not good at all. When a job seeker announces a reason for leaving, it's offering a basic defensiveness, an implication he has done something wrong. Sometimes that might be true, but you certainly never would want a prospective employer to learn about your possible negatives before hearing all about what you have to offer. As I love to say, you focus on the sunshine, light, and success.
Here's what you need to say (in language that makes you comfortable) - IF ASKED, and only if asked. That may come in the form of "So why are you looking for a job?" or "Are you still with your former employer?" or something along those lines. Remember, no pre-emption on this topic or you’ll look like you're trying to hide something.
"I had a great experience at XYZ. I was able to learn _____________. The job started to change a few months ago when several people were let go. They needed more administrative help in the office, and, unfortunately, a lot of that fell to me. While I'm relatively competent at that sort of thing, it's not my major strength. The work I was doing before that was! The admin aspect escalated, and I realized I was going seriously off-track on a career path I had grown to love--and excel in. I also realized looking for a job while putting in long hours there was not feasible, so I decided to leave and devote my time to a serious search. We worked out an amicable separation."
Some HR professionals (and I hope you get to avoid them at the beginning of a process of interviewing, and only see them at the end) may immediately say "Why would you leave a job before having another?" I think this shows a lack of understanding of current job markets, but it still is asked frequently.
Your answer is that there was no way you would be able to find enough time to do a smart search while working long hours. As it was, you already had put out some feelers, and found it very difficult to make time to even go to first-round interviews. That's when you realized you were going to have spend more time to do it right.
If you’re asked whether it’s okay to contact your previous boss, you can say that after all the terminations and resignations, he/she was not happy about your leaving--and you're not comfortable using that person as a reference. HOWEVER, you do have someone who knows your work well . . .
Of course there are a lot of variables in dealing with this situation, and it will change significantly from person to person and organization to organization. The key is--you do not need to "fess up." What you need to do is answer only when asked, and then position it in a way that reflects well on you.