What makes you think the capsules won't give you "the bad mood changes"? If it's an ingredient you already know to be in the pills and not the capsules then go for it. otherwise I'd maybe try something other than oxycodone. there are plenty of alternatives.
The capsules are immediate release and the pills are extended release, right? I can't take hydrocodone also. I don't want to take a more powerful drug like oxycotin or morphine, so I was hoping there was a different chemical compound in the capsules!
Oxycontin is just oxycodone in extended release form. It is no more powerful than immediate release oxycodone. And morphine is actually less powerful than oxycodone. Oxycodone is 1.5-2 times stronger than morphine. The shape of a pill and whether the pill is a tablet or capsule does not tell you if it is extended release or immediate release. Avinza is extended release morphine than comes in capsules versus tablets.
It sounds like you are having intolerable side effects from oxycodone. That means no oxycodone, whether it is a tablet, a capsule, immediate release or extended release Oxycontin. As the first replier stated, there are other medications out there that don't have oxycodone in them.