Why is itunes deleting songs from my iphone 4s?

So, I've had this happen at least 5 times now Over the course of a month.

I put about 20-30 gigs of music on my phone (WHICH TAKES A LOT OF TIME TO SELECT), its fine.

Then, if I connect my phone to itunes anytime after that, I have nothing but "purchased" songs on my phone.

I have "manually manage music and videos" checked

and "sync only check songs and video" checked as well.

Never had this problem with the previous version of itunes.

And I've narrowed it down to only happening when my My computer is connected to the internet,

via wifi OR when my iphone is connected to my computer via wifi.

Its really not too cool to be honest with ya.

I don't want to stream music, and as paranoid and cynical as it sounds,

it really feeels like apple is trying to force me into Beats subscription or itunes match or icloud, etc.

I'm not interested in any of that. I simply want to put songs on my phone and go, with the ability to add songs later without them being deleted.

Thank you for any help you can contribute.

Version is itunes 12.1

ios 8.2.