Here are two approaches. I recommend the second.
The first one probably looks better, but is less honest (and dishonesty while applying for a job is Very, Very Bad):
February 2015 - present: Seeking employment.
September 2013 - December 2014: Earned Masters of Something degree from College University
No one will likely ask what you did in January 2015. (See also other approach.)
The seven month job search isn't unusual. You may be asked (verbally) what you did during your job search. You should be prepared to describe (verbally) what steps you took during that time. You don't need a a long, detailed list, but you should describe something that normally takes a few months. It may be hard to answer in a way that's both honest (never lie while applying for a job) and positive.
Now consider a second approach:
August 2015 - present: Seeking employment.
September 2013 - December 2014: Earned Masters of Something degree from College University
Now it's clear you took several months off. You may be asked (verbally) what you did during that time. You should be prepared to describe (verbally) some things you accomplished, or at least tied to do, during that time. ("Recovered from grad school" is a good and honest way to describe some of it.)
Beyond that? Think back. What were some of your specific goals (aside from finding a job) from February through July? If you use any kind of calendar, see what was scheduled for that period. Any accomplishments during that period, work related or not, are good things to mention. Failure is an option; you may have to use the word "tried." (If possible, don't use it more than once.)
There may be days you didn't even get out of bed. Don't worry about them. Most of us have had them. You had them more frequently than you wanted. Sunk costs, move on.
Words not to use: anxious, burned out, depressed, etc.
Finally, as Joe Strazzere mentions, ensure that you really are recovered. Anxiety attacks and depressive episodes are no joke. You "just get over them" about as well as you "just get over" a seriously broken bone. Medical care is usually required. Getting care may increase the size of the gap, but there's little sense in getting a job but being unable to perform well. If I needed to do that, I'd say something such as
I got into a kind of bad place, and it took time and effort to get out of it. That's behind me; I'm looking forward to working at the Example Corporation, and I'm confident I'll do well here.
There's a great existing discussion elsewhere on this exchange: How do I explain being unemployed for nearly two years due to untreated depression?
By the way, I've read many thousands of resumes, and conducted hundreds of interviews. If you'd like to practice some answers, run them by me and I'll let you know how I'd judge them in a real interview.