Passing music from CD to iTunes to iPhone 6

I usually buy music on iTunes and save myself all this trouble, but the CDs were on sale, so I got them, and my phone randomly deletes them off my music.

They pass on iTunes just fine, but once I put them on my phone, they will either not show up at all, or they'll be on my phone until i connect it back to iTunes or restart it, and then they'll be gone.

I have it on "manage manually" and still nothing.

Any help?