I feel you. It's an extremely stressful, prolonged waiting game.
This is my first time applying to MFAs, and I only applied to 4 very high-profile schools in places where I'd want to live. One of them is a looming ghost of a rejection (acceptances have already gone out); my top choice started calling the accepted yesterday (no call yet); the other two should start calling any day now. The stress threatens to overwhelm, so I distract myself by going to the gym, hiking, meeting with friends, playing video games, and generally practicing the Parks & Rec motto of "treat yoself."
Oh, and generating new work. I can't stress enough how much I agree with previous posters, that this is the key to success in the arts! Define "success" how you will, but if practicing your passion while still being able to pay the rent is "success," then it should be relatively easy for those who are driven, passionate, and dedicated. Some of my favorite work that I've ever written came out of me within the two months after submitting MFA applications. While those incredible poems didn't make it into the writing samples, they will end up being published somewhere great (he says with zero proof and zero consequences), and if I don't get accepted to any of the 4 programs I applied to this year, they will end up in a truly outstanding writing sample next year. And you know what? I have gained more self-knowledge and craft skill from pouring myself into my work post-applications than I have in a long, long time. Perhaps more so than my last writers' conference.
Regarding "competitiveness" and being "the right fit," I'll also add that I only somewhat even believe in the former, but 100% believe in the latter.
I have an MS in a hard science from a very respected institution, been published in one of the "top three" (whatever that means; I'm parroting critics here) poetry magazines in America, attended many weeklong writing workshops, been a poetry reader for a major American litmag, and have recommendation letters from a National Book Award winner and a National Book Critics Circle Award winner (who only got into Iowa on his second try). I also think my writing sample is pretty bomb. Now, here's how I view my subjective "competitiveness": it's subjective. I'm sure the applicant pools are full of people with my credentials, and many with significantly "more," just as I'm sure there are plenty with "fewer" credentials. That's less concerning or important to me than realizing that each program has a culture, an agenda, and a literary style. I've had to throw away considerations of "top ranked" and "most prestigious" when honestly assessing where I'd be happy in an MFA program. I'll likely get a rejection from Iowa in the coming days, and I'm A-OK with that, because I realize (now, only after applying) that I'm not a good fit there. I think I'd be miserable there. My poems are nothing like anything I've seen from their graduates, and their emphases in scholarship and academia are not in line with my overall goals.
While the admissions process is laughably imperfect, and obviously mercurial, I do have some faith in their ability to weed out "poor fits" for their programs. And, frustrating as it can be at times, I have honestly come to appreciate it. Maybe my (likely) impending rejection letter from my top choice will have little to do with my being a proper fit for that program, and more to do with the sheer number of "good fits" (of which I'd ostensibly be one), and their simple inability to admit or waitlist all of them. Nothing personal, just numbers. Do this hurt to imagine? Hells yes. But it's how I know I care. It's how I know what's important to me, so that I can continue to devote myself further.
The last thing I'll add is that, after having a career for 8 years in a field completely unrelated to writing or the humanities, I've decided--if I don't get into an MFA program--to quit that career and move to New York City, a place where I can find and immerse myself in a literary community that fosters and strengthens my craft. It took me a decade to admit to myself how important poetry is to me (not to mention a decade to actually get good at it), so I'm done messing around. I can pay the bills one way or another, just like I have previously, but this time it's going to be in a place where I can do it as a member of an artistic community. Which is exactly what I'm looking for in an MFA program.
All that being said: I've made some difficult but important choices for my own artistic endeavors, which result in a win-win, even if I'm rejected from every program I applied to this year. Is that my preferred outcome? No. Will that seriously hurt? Yes. But I'll make the move anyway; build my own community anyway; and reapply in the fall.
Best of luck to you, and I sincerely hope you can overcome your self-doubts. If you truly love the art and the work it requires, you will succeed, even if it means more rejection letters. This is coming from a guy who has "rejected" his own art for many years, and after having finally "accepted" it, is more empowered to take the reins himself, to be the poet he wants to be, regardless of what some admissions panels think. This perspective is difficult to find and hold onto on February 28, but when it can be obtained, it is all the affirmation I need.