Congratulations! I want to point out that going from 5 to 6 kilograms is, in fact, a huge jump. That is 20% more than what you were doing before, which is literally huge. That is a big accomplishment -- and also, you won't have to jump by that much in the future.
This is an unfortunate paradox for people at the beginning of their workout careers: the smaller weights are harder to move up in, because each step up is actually a pretty large percentage increase.
going from 5 to 6 is 20% more going from 6 to 7 is 16.7% more going from 7 to 8 is 14% more and so on
So eventually the next weight will only be like 10% more than the previous weight, and that's a much more reasonable amount to increase by. If each new dumbbell set feels way harder than before, just know that the next step up will be easier than the last one you just did.