I cosleep. This is my second baby and I resisted it due to all the 'put them in an empty cot' advice.. I also didn't say to most of them I coslept until my health visitor who said as long as you're doing it safely thats perfectly fine. Here is the lullaby trust link that you may have already read : https://www.lullabytrust.org.uk/safer-sleep-advice/co-sleeping/ Most second time mums I've talked to have coslept and its made things easier second time round. Sleep is pretty crucial when running around after two esp to mental health. My baby still cries and I've been up for the last hour or so as my baby is trying to pump out a bit of wind. Fourth trimester is the longest but contact with the baby gets them through it. I also bought a sling for the day time which has given me some mobility to play with my first and given my baby some good sleep. I also have found going for a walk outside has made her feel better when nothing else has worked to stop the crying.
Cosleeping is more nuanced than black or white but opinion aside; yes you should have told your doctor exactly everything you have been doing to try and help. Without knowing the whole story/picture the doctor can't help you much. You should address this issue and ask your doctor if she thinks he might just be a colicky baby. Colic most often starts when a baby is between 2~5 weeks old and yours sounds like it fits the bill so I suggest asking/inquiring about that.