How do I react to pikemen as a cav civ?

Can anyone tell me what should I do when I am a cav civ and my opponent starts making spearmen in feudal age?

I don't know how to react, my instinct would tell me to make archers but I need to build a gallery for that, invest wood and gold for units/ technologies I'm not going to use later in the match.

It just all seems like a waste of resources to me and I lose everytime because I refuse to waste resources like that, I usually don't take the fights and try to rush to castle age so I can get some scorpions or that I can yolo throw my castle age knights to feudal spearmen.

I mean when I am archers and I get scouts is not that hard to counter, I already have the barracks and it's only wood and food, although I don't know what to do too if my opponent gets skirms, same problem, I don't want to build a stable??(forgot the name) for something I'm not planning to use later on.

Any advice would be helpful thank you.