Well I'm not going to be the only one that replies
But you should consult the doctor.
And as far as the curve goes, penis curves are natural. Some bend way up and way down, way right and way left. There aren't many completely straight peckers out there.
Problems maintaining an erection aren't exactly normal, and I think you'd get a lot out of going to the doctor for a checkup and to ask questions =] it's a sure-thing