I don't wanna lose her but should i still tell her how i really feel?

Ok, let's look at the facts: she has already stated that she isn't looking for a relationship; you are madly in love with her and want a relationship with her and have shown manifestations of your feelings for her with words, cards and flowers. I am sure that she was happy with the flowers and card. Just go up to her and say that you would like to be more than friends. Her response should indicate her feelings. Pay attention to her response.