i can't remember the name
so basically girl likes the glasses's guy's best friend but ends up falling for glasses guy. they both have a rubber duck keychain. but just when all is going well for the glasses guy and the girl comes in the other girl who is a needy psychotic slutella who is nothing but a major burden for the glasses guy. she's so psychotic matter of fact she called the heroine non stop till the heroine developed a phobia on answering phone calls. anyways the glasses' guy's best friend end up falling for the heroine and knocked her up but thought that it wasn't his but the glasses guy because the glasses guy spent the night with the heroine i forgot why. so when word of the heroine being pregnant spread around school things just got out of control well sorta but anyways the glasses guy took up the responsibility of being the father and got suspended for admitting that he was the one responsible...i hope i have given enough information XD

Kare wa tomodachi for the first few sentences of your description. Not so sure about the rest...