It's like in English "I" is the Nominative case and "me" is the Objective case of the same word.

In Ukrainian "шведа" is Genitive and Accusative cases of the word "швед" exactly like in Russian.

Here are all possible cases of the word "швед" in Ukrainian:
Singular: швед, шведа, шведові, шведу, шведом, шведі, шведе
Plural: шведи, шведів, шведам, шведами, шведах