僕も君と同様楽しくない。

。

I'm no more having fun than you are.

Literal

I-[also-も] you [with-と] same-manner fun-not.

~と同様 ('the same as, just like') is a formal/written way to express similarity — stiffer than ~と同じ or ~と同じように. 楽しくない is the negative of the い-adjective 楽しい ('fun, enjoyable'). The combination 僕も ~ 楽しくない gives 'I too am not having fun' = 'neither am I.'