Constipation SUCKS!!!

So where do I start? Jonathan is doing good with therapy he is looking left and right is putting things in his mouth, after you put it in his hands. He is not holding his head up, so much for heads up at 4 months but I know he's a preemie and there are bound to be some delays its just in the back off my head, I know all babies develop differently! He is doing a little babbling he is big on smiling. he tries to laugh but what comes out is so soft and cute, he's starting to cry where you can actually hear it his cry is louder I never thought I would love to hear him cry! He is still off BP medication, we go back this wednesday to check it, we have an appointment with U of M for his hearing on the 30th!!! He is weighing 12 lbs 3 ozs As I last wrote he is on cereal(oatmeal) and eating a lot of it, so on friday I gave him 2ozs he ate it all! On sat. he slept all night getting up only once and then up at 10am back to sleep at 1130am then didn't get up till 3pm very weird for him, so of course i called the doc, since he didn't have any wet diapers the end result was they wanted us to come in at 430pm! Well at 330pm Jonathan smiled at me and it was everywhere poo from belly to toes he was back to my little baby, so I called the doc and told him what happened he asked, "how much cereal did you feed him?" He was floored he said that was way to much for him, how was I supposed to know, he ate it with no problem, so were back to 1/2 to 1oz, however it hasn't helped the constipation he arches his back, cries and so does his mommy and is just miserable for like 20 mins after eating, we see the ped. monday and see what we can do! He is starting to hit I don't know if that possible but if he doesn't want his bottle or he doesn't like you in his face he hits the bottle or your face, maybe he is just wanting to touch or he is just going to be a brut! He went into the lake for the first time he cried at first but didn't seem to care. We leave for Michigan adventure in 3 weeks we are staying at a resort and Jonathan's cousins are going to be there too, were going to have so much fun!