I'm the biggest critic of Russia there is, but that country is not going to invade Poland in a month of Sundays. For a start, the two countries don't even share a border, apart from the Kaliningrad exclave.
That's not to say that Poles are not understandably worried.
Putin's tactic is most likely to stir up trouble in neighbouring countries for two reasons
1 - to bolster his esteem and support at home, being paranoid of going the way of his partner in crime Yanukovich in Ukraine
2 - where he thinks he can stop what he perceives as the "encroachment" of the West on his "patch" tho that is to a degree for the same reason as (1).
Poland to all intents and purposes has "flown the coop": a member of native, and increasingly prosperous. He doesn't have much leverage over it. In contrast to the Moldovans and to an extent the Ukrainians. But he's plainly over-reached himself in Donbass, his original idea of a "Novorossiya" incorporating the south and east of the whole country having had to be shelved.
Any military aggression anywhere is most likely to be in the form of the sort of sheaky "little green men" approach used in Ukraine, or indeed in any country, such as Georgia, Armenia or Moldova, where the presence of so-called "peace keepers" can be used as a pretext effectively for annexation. In that respect Latvia is probably the country with most to fear, but if he can't even do it properly in Donbass there's little prospect of it working there.
To be prepared and properly forearmed is wise though.