Oh no no no no!!!! Her problems are not because her ears aren't cropped!! Please don't EVER feel bad that you didn't have the ears cropped!!!
Sounds like she might have a hematoma, which can happen in any dog with floppy ears, but I personally don't think that is any reason to crop a future Dane. My boy Connor is cropped, not my choice- I adopted him that way- and he is scared to death to have his ears touched/cleaned/examined now because of the trauma of having them messed with his entire puppyhood. With cropping you risk infection of the edge of the ears, and then there are months and months of taping and trying to get them to stand right, what a mess, and I just don't believe that it is better for the dog in any way. It is purely for "the alert look". I have heard some people argue that it helps prevent inner ear infections, but I think that is a far-fetched idea that helps some people justify cutting their dogs ears off for looks. I know there are people who will strongly disagree with me here, but this is what I believe.
Leeloo has floppy ears and they cause her no problems at all. If your pooch is having problems due to flies, there are several products on the market which will help repel them. I just don't think the answer to ear problems is cutting off the ears.
I know you will make whatever choice suits you and I would not judge you for it, but I just don't think cropping is the answer. I think the answer is proper care and prevention, and awareness. I am not trying to offend anyone here with my opinions, but I can't hold in my feelings on this issue! Thanks for letting me express myself!
I hope your pooch feels better soon!