it doesnt mean twins usually, i know i definatly looked like i was carrying twins as well, no one believed me i was 3 months, i looked about 5months........... you did just have a baby 7 months ago, that actually means a lot, as to how soon you show............ the gaining weight, please dont brush it off as being pregnant, you do NOT want to deal with that after giving, control your calorie intake.......... believe me, your baby will be healthy and everything with the minimum of "normal" daily caloric intake.
Yes it could be! Or a lot of gas =(