Is this about chemistry class?

Chemistry as a subject / science

In that case, I would leave of LEARNING (since you’re talking about the class/subject) and just say “Chemistry didn’t come EASY to me”

And: “TO me, chemistry didn’t come easy” although I don’t think there’s any reason to invert the sentence - it seems too emphatic

Is it an overstatement to say “I was bad at chemistry” here?

I wasn't good at/in chemistry

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for me, chemistry didn't come easy

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In that case, I would leave of LEARNING (since you’re talking about the class/subject) and just say “Chemistry didn’t come EASY to me”

I understand “Chemistry didn’t come EASY to me”? but what's wrong with learning? It doesn't come easy to you only if/when you learn it, be it a class or at home on your own.

Is it an overstatement to say “I was bad at chemistry” here?

I'd say that the meaning is a little different. You can be bad for different reasons, e.g. because you are lazy.
"плохо давалась" means that you lack natural capabilities for this subject because of pecularities of your mind. You can work hard, but the result is poor.

I agree !

LEARNING is redundant there since “not come easy” already refers to difficulty learning