When I got unemployment in Germany, I made use of a technicality to just include it (properly identified) in with my earned income. The technicality had to do with how unemployment insurance is handled in Germany - which is different from how they do it in the US.
This is the IRS tax topic on Unemployment Compensation which includes a link to their publication on the subject. Tax Topics - Topic 418 Unemployment Compensation
Depending on how the Dutch do unemployment compensation, you may be able to either exclude it altogether or just lump it in with your "earned" income or some other, simpler treatment. Depending on the amount involved, you want to try to go with the simplest approach.