Although females get a slight bulge towards the very end, typically a "belly" is the sign of internal worms/parasites. Mine are on a 10ish day cycle. Day 1 lay, day 7 hatch, rest 3 day, restart. If she maintains the "belly" for more than 5-7 days, I would recommend a quarantine and de-wormer and parasite removal.
How long have you had her?