Natalia: I really feel for you. I wish I could say something to make everything ok. It is good you are seeking medical attention for possible PCOS. It sound like you have low self esteem and are punishing yourself for whatever reasons and don't think you deserve to find someone. All I know is that you wont find a man to treat you well if you dont feel like you deserve to be treated that way and you will end up with men who will hurt you.
I know it is easier said than done, but you need to learn to love yourself before you can love anyone and anyone can love you. From the way you talk it sounds like something terrible happened in your past that you have not been able to get over. Wehn you see your Dr about PCOS you should also speak to them about how you are feeling. It sounds like you need regular councelling. Try and get out for 30mins of regular exercise and fresh air. I know if I don't I end up feeling really down.
I do hope you can find the strength to overcome these problems, there is no reason you can't find someone special, love can be found in some of the most unsual of situations. Keep and open mind and heart.