Price indeed bounced at the 78.6% of the wave X (retracement) of the FOMC bullish momentum (indicated as wave W orange).
A bullish zigzag (ABC magenta) could occur within Wave Y (orange).
Currently an ABC (blue) zigzag correction is probably the most likely wave explanation with wave C (blue) targets above.
Price has bounced at the 88.6% Fibonacci support when placing a retracement on the bullish spike during FOMC.
Price bounced at the wave X (magenta) resistance as part of a potential bigger wave 4 (dark red).
A bigger WXY (magenta) correction could be expected after the bearish momentum during the FOMC statement.