In English, if you say you "feel badly/terribly" it means that you literally cannot feel things well (like when wearing mittens (adverb)). When using the word feel in regards to health or emotion is to say you "feel bad/terrible" (as in my health is bad (adjective)). These are different parts of speech with different grammar rules. :)
it's ~poh-hah-noh, Ukranian is much more consistent with it's vowels and consonants than English. If that's not clear to you, here (since you know the languages at least to some extent) are explanations using the pronunciation of Swedish/Norwegian: ~på-ha-nå and Finnish: ~pohano. I believe (correct me if I'm wrong) using Russian you'd also pronounce it well, but remember that г is "h" in Ukranian.