Oh and I don't like Sudafed because it's not safe for women themselves, nothing to do with breastfeeding. Sudafed has been linked to strokes in otherwise healthy young women.
Most people do diet for 6 weeks and then often take another few months to get pg.
You don't have to lose as much weight as possible - any weight will help. I only lost 3 lbs right before I got pg with my DD.