"I am well, thank you."
Translation:Táim go maith, go raibh maith agat.
because romhat and raibh aren't the same word. Romhat is like "to you" or "with you" where as raibh is like "let there be"
go raibh = let there be
maith = goodness
agat = with you
tá = there is failte = welcome romhat = with you
it looks like romhat and agat mean the same thing but they don't, they are different prepositions, they just both happen to be like "with" here.
Note that agam does not mean "I have". Tá X agam means "I have X", but the verb is Tá, and it is only the combination of tá and ag that gives you "have". For the past tense, "I had X", you use the past tense of the verb - Bhí X agam.
And to take matters further, the combination of Tá and ag doesn't always mean "have" - Tá fear ag an doras means "there's a man at the door".
If by "states of being" you mean things like "I am happy", or "I am hungry", you typically use the preposition ar with a noun in Irish (tá áthas orm, tá ocras orm) instead of the predicative adjective, but there are many such cases where you do use a predicative adjective - Tá sé marbh, Táim sásta, for example.
How complex is this language actually? Lol. I'm starting to think my native language, German, would be easier to learn. So many phrases mean something totally different when you translate them directly (as I've noticed reading these comments) and it feels like the only way to get a hang of it would be to go live with an Irish family as an au pair or something lol