Results are on Sunday because that is the offical voting day across Europe. Aka, the rest of Europe votes Sunday.
As for the far right gains. The EU vote has turned in most countries into a protest vote against the sitting government. It has rarely anything to do with the EU it self. That is why parties like the UKIP, BNP and other far right nationalist often racist parties get high numbers.
Personally I think it also reflects how people see the EU parliament. They still think that the EU parliament has no power (aka the parliamen 15 years ago), which is only partly true. While most power in the EU still resides with the member governments, the EU parliament does have its say, especially when it comes to the budget and EU commissioners. But yea it is not a "true" parliament like most countries have.
But in certain countries including my own, the EU vote has turned into a some what farce since every crackpot racist nationalist jackboot comes out of the seems and gets air time. During a national election they would not even get close to the door of the building where the real parties debate in a civilized maner.