Excessive staining and feeling like teeth moving

I've been to my dentist and hygienist and both of them are stumped by this so hoping someone may have some suggestions.

I have quite a lot of staining on my teeth that appears quite rapidly (3 - 6 months), my dentist said it is the staining similar to those who use Corsodil mouthwash for extended periods of time although I have never used this mouthwash.

I don't smoke, don't drink wine, don't work with any chemicals. I brush (electric) with sensodine toothpaste (the whitening paste made no difference), use listerine mouthwash and satin tape twice a day.
I drink 1 latte most days, 1 glass of fruit juice and almost clear herbal tea the rest of the time. I very rarely eat anything like beetroot that is likely to cause staining.
My dentist says there is nothing I have mentioned that would explain the level of staining I have, he also mentioned that I clean my teeth very well.

Can anyone think of anything else that could be causing the staining?

Also, for around 2 years now, it has felt like my teeth are loose and that eating and drinking will make them come out. Again, my dentist and hygienist have reassured me that they are not moving at all. My dentist did an X-ray and said there is some bone loss but nothing that should cause this feeling.
When I had my wisdom tooth out, the max-fax surgeon said I have receding gums, is this likely to cause the feeling?

Thanks in advance for any help :)