Congrats on growing your following! Twitter recently changed their requirements and made it somewhat easier to get verified. However, I've seen where people have to apply as many as five times before Twitter finally approves them for verified status. Make sure you are really focused on having your profile look extremely legitimate and keep applying every 30 days!

As far as losing followers, if you're using a tool like Tweepi or ManageFlitter and unfollowing people, it's possible they are utilizing a similar tool and will pretty quickly unfollow you as well. Really can't think of any other reason for that to be happening, quite an anomaly. Keep an eye out for trends and start making notations to see if you can further decipher why you're randomly experiencing a drop off. Twitter Analytics might be worth looking into as well.