It's likely that you are dehydrated - drink lots and lots, more than you think you need. I'm bf a 10mo who eats a lot of solids too, but am putting away 2l of water every day, plus herbal teas and occasional juice.
Your baby is likely to be feeding frequently to satisfy thirst, hence the many brief feeds.
Babies will feed more often in hot weather as they need more fluids, but this is normal and your supply should adjust. Make sure that you drink plenty, it won't affect your milk supply but feeding more frequently in this weather could leave you feeling a bit dehydrated.