take care of yourself so you can take care of the baby
Kudos to you for breastfeeding. Top tip from someone who has been there and done that with both the nursing and the c-section. Just be gentle on yourself. Do not try to diet at all - just nourish yourself with the best food you can, and allow yourself cake if you want it.
Yes, you may feel like you're not losing the weight - but you'll notice your milk supply may get compromised almost immediately you drop your calories.
Stay off here for the time being, don't dash back to the gym - some walks pushing the baby around, and perhaps in a few weeks some pilates to help strengthen those abs, are all you need right now. Plenty of time later for the hardcore stuff.