You need a punch in the face!
I've had Chinese and European boyfriends. I'll tell you why I prefer European guys and the possible reasons why you're not having much luck with the Polish girl or any girl for that matter.
1) Women don't like 'wet blankets' like you. What's wrong with you? Some people say that Chinese guys are not their type and you suddenly change your mind in chasing this girl? They tell you to cover yourself in poo and jump off a cliff, you'd do that? I think so. Get a spine!
2) You have zero self-esteem and only see the negative. A lot of people are giving you positive suggestions and you keep repeating you're giving up. Low self-confidence and negativity is a real turn-off! And the last thing us girls want to do is be your mummy and reassure you all the time. And who wants to be with a guy who sees a little problem and jumps ship?
3) Your attitude toward a whole group of people makes your personality not very attractive. Just because you hate yourself for being Chinese, you don't have to lump all Chinese people together - so you've met every single Chinese person and spoke to them all have you? Every culture has their way of doing things. In one culture what is seen as good manners (eg in Japan slurping your noodles tells people you think it's good) in another country is seen as bad manners. It doesn't matter if you were talking about the Polish, French, Japanese etc, the fact that you're so narrow-minded is a big turn-off.
4) You keep putting yourself down, telling us you're not physically attractive either. Well, you may not be able to do much about that but you can always work on your personality.
I prefer European men because they make me feel more feminine and protected. I've had 2 Chinese boyfriends and they were 5'11 and very well-endowed so it's not always true about size. When I watched the Korean movie 'Daisy' I fell for the assassin character in it (see link).
I think in the end, everyone has a type they're attracted to, but I always find that when the personality is attractive and the person is physically attractive but not your type, and you slowly fall in love, that person soon becomes your type.