Just don't have any expectations and be willing to relearn a _lot_ of your social interactions work. Poland can be a great place to live but it's not a user friendly country and you'll have to accept the way things work here and get over any nagging feelings that Poland is a defective Canada that can be made more like your homeland.
bits of advice:
Any Polish person who _insists_ on speaking English with you and discourages you from learning/improving your Polish.... is not your friend, they see you as a resource but will eventually get tired of you and dump you.
Don't nod to or greet random people on the street as they pass (it's a hard habit to break but you'll get the hang of politely ignoring people). Do always greet people you know.
Do continue to learn Polish (hint: pay more attention to nouns and adjectives in the beginning - that's the backbone of the language and getting those right is more important than verbs). Don't over-stimulate yourself. Find a local online newspaper and just read the headlines (with google translate and a dictionary) until that gets too easy. Don't start off trying to read things that are too difficult (like Rzeczpospolita)
Donald Duck comics are very helpful in learning the language.
Better produce and baked goods and meat are generally found at smaller neighborhood stores, it would be good if you could accompany someone who knows how to shop there to learn how to ask for things. Weight is usually ordered in deko (decagrams so that you ask for 30 deko rather than 300 milligrams).
Polish people are not rude for the most part but rules of politeness are drastically different from English speaking North America and you'll sometimes need to be rude by Canadian standards to be polite here and trying to be Canadian polite will make you seem intrusive (politeness is largely about maintaining social distance).
Don't over apologize, it's not part of the politeness culture and will be seen as a sign of personal weakness (and a sign you can't be relied upon).
Polish people... distinguish grades of friendship. It will be a long time before you're more than znajoma (acquaintance) and make it to koleżanka (friend/colleague) you'll only very rarely ever made to przyjaciółka (very close friend) and never be kumpelka (close friend by the implication is that you've known each other for years).
Learn to stand up for yourself (it will be needed).
Learn to say "No." to requests (it will be needed).
Don't stress out after making mistakes. You'll get over it and so will other people.