Oh, what a fool I feel! 
( ( Oh ( , ( ( what ( a fool ) ) ( I feel ) ) ) ) ! )
(ROOT (S (S (INTJ (UH Oh)) (, ,) (X (X (WP what)) (NP (DT a) (NN fool))) (NP (PRP I)) (VP (VBP feel))) (. !)))
I cannot believe I just did that.
( I ( ( ( can not ) ( believe ( I ( just ( did that ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (MD can) (RB not) (VP (VB believe) (SBAR (S (NP (PRP I)) (ADVP (RB just)) (VP (VBD did) (NP (DT that))))))) (. .)))