Exp. point

Hello, since few days, I noticed my pokemons don’t win a lot of exp. point when I win a battle (against a wild or a trainer). I remember I won something like 2000 exp. points or 3000 against Harmony or East. But, now, I’m in Selene city, I fight pokemon in level 60 to 70 an I win only 1000. I don’t understand… Is it just in my mind?

selene city gym trainers give low exp, plus there is an exp decay mechanic in the game, where if you both fight a level trainer with a level 1 pokemon, and a level 5 pokemon, the exp gained by the level 1 will result into a higher level than the level 5 one.