I personally wouldn't give a baby solids at that age for a variety of reasons, the main one being that their digestive system just isn't ready to cope with it. Also starting solids isn't about a meal as such but rather encourging tastes and textures and getting them used to feeding from a spoon etc instead of a breast or bottle. Have you tried giving him more milk feeds? At 3mths of age they can go through another growth spurt and also their appetites can increase anyway. Another cause could just be developmental as well - they are starting to learn so much at that age - they become more involved in play and can start to hold toys and be more interactive in general. I would be eliminating all of these reasons first before making the leap to solids as it is possible that even with solids that you will be left with the same baby kwim?

But in saying all of that it is your decision as his Mum what is the best for him.