Nikon D5100 camera issue?

I'm currently looking for a solution to a problem with my Nikon D5100. I have owned it for 2 years now, and have had no issues up to now. Last week I switched lenses (the same way I always have) but when I take pictures now, something is obstructing the view internally. I have tried several lenses to make sure one of those is not the issue, so I know it's internal. Anyone know what's up and how to fix it? Example of a photo showing the obstruction attached. I have not dropped it, so I'm not sure how or why it started doing this. Thanks!

Looks like the mirror is stuck. Maybe you hit it when you changed lenses. I'd look inside the body to see if I could very gently do something about it.

If not, then it is time to have the camera repaired.