You're all good mate.
I'd be willing to bet that what you're experiencing is purely mental.
I went through something similar last year and basically became asexual for about 6 months. I think there was even a period of about a month when I didn't even masturbate.
It was mainly down to stress, a very nasty bout of depression, and basically just a lot of shit going down.
Don't let the fact that you're not getting aroused freak you out though. Just deal with the shit in your life that needs your urgent attention, and once you starting dealing with what ever issues you might have, you'll find it will come back.............in my case it came back with vengeance
Take it easy dude, I hope you find your mojo again soon :-)