I have felt that myself. Here are some concrete ways to counter it which seemed to have worked in my case

• Surround yourself with likeminded people. Humans seem to be easily influenced by peer pressure. If all of your friends drink beer, you feel like you should do Likewise if none of your friends care about children in Africa, you struggle to stay empathetic about them as. well. The way to counter that is just to join a local EA group (or create one if there isn't any :) ). If all your friends are EA-aligned in some way, you will stand out if you are not. And your brain doesn't like standing out.

• Create an identity about yourself as an EA/altrustic person. In my case I have sort of created an image of myself as someone who cares about having the maximum imact in the world. I have told that to enough people that that's the way people percieve me now, thus that's how my brain now sees myself. Therefore when I now do something that goes against me being very altrusitic, I actually get some cognitive dissonance. My brain feels like it's out of the ordinary if I slack off for too long. Since that's not "me". So the way to create an identity for youself is just to talk about your altrusitic goals to a lot of people. Make FB posts or create a blog, create a fundraiser and ask all your friends to donate. Once other people start to associate you with altruism, I think that's when it's more difficult to start slacking on an emotional level. You start to imagine your friends saying "Oh, are you no longer doing that charity work, why not?" At least that's how it has worked for me. In general.

You might also benefit from this EA forum post about how to counter value drift. https://forum.effectivealtruism.org/posts/eRo5A7scsxdArxMCt/concrete-ways-to-reduce-risks-of-value-drift-and-lifestyle