Yes, I have that doubt too, the new government might be anti-EU or make some strange decisions concerning what is previously agreed, let's see what happens, but to be honest I don't believe they will leave the EU.
I am from Lithuania, and I would say that there is a strong anti - Russian and especially anti - Putin sentiment. I would say that noone really fears Putin that much and sees him as a little bit of an idiot. However, it is still quite likely that Putin may at some point try something with the Baltic states but we always have NATO to protect us.