Don't take it personally, man. "Not a good fit" can mean about anything. I had three interviews with a company recently where I absolutely nailed every requirement and every interview only to end up hearing my experience wasn't a good match a month later. I was disappointed, as I could have knocked that job out of the park (in my opinion), but I'm confident that the right job will come along soon enough.
Really I can look back at my career and see several of those moments. I worked for 3dfx Interactive back in the ol' days and was crushed when they closed down and I got laid off, but it was for the best (ended up making way more elsewhere). Got laid off again a few years later right after my son was born. It was panic mode at the time but it ended up working out in the long run there too.
In other words, keep at it, man (or ma'am). Don't take it personally. Don't expect loyalty or caring from a company unless they earn it. And don't stop working to improve your skills and improve your position. Every job experience develops you as an employee and increases your value, and every time you interview you get better and better at it.
TL;DR you got this bro/sis