Also, with the warmer temperatures, sometimes they are more prone to spitting up. They don't call them happy spitters for nothing!!! I would continue to keep a close eye on him to see if any other of the signs or symptoms that Wendy mentioned begin to come forth.
With my Thomas, he started out great, but then things went downhill like a mudslide. Many "innocent" symptoms were really indicative of food intolerances, but he appeared so healthy that they went undetected for 15 months. Some resistance from the pedi also came into play. I would begin to write down things you are seeing in relation to how he sleeps and poops. i would also write down foods he eats and when he spits up. Our memories become very hazy when we have to recall a month or 2 of time at one appointment. Writing down his schedule or lack therof may give you some insight. i really wish I had done it sooner. Just the fact that you even mention food allergies and based on your login name, it sounds like more may be going on.
Good luck.
Jen