First kiss (kinda)

So my serious gf and I recently broke up after 3 years. I’m still upset and sad about it. But I was telling my best friend since elementary school about it and he just spontaneously kissed me. I was surprised, but I liked it and reciprocated. I’ve never even thought of him like that or ever even thought of a guy in that manner. Now every time I’m around him I get butterflies in my stomach and feel like a giddy schoolgirl, and he’s the same way. Do I pursue this?