All of this is completely normal development.
But you also have some outstanding things in the mix so that makes it harder on YOU.
Kids eat when they are hungry. Just keep offering healthy options. This comes and goes.
Teething is painful, it can make his gums feel like little needles are poking through, but then from grinding and chewing his jaw can become really sore. Tylenol can hep with this soreness.
Allergies are terrible right now.. everything is blooming and he has tiny sinuses and his ear tubes are tiny, all of the drooling and teething does not help.
He is beginning to come out of that baby fog and see that there are things going on around him he cannot control. It frightens him. Imaginations can really run away for him and he can now recall dreams. You can talk about how dreams are like stories. My mom used to tell us, if we wake up from a bad dream, roll over to our other side ad the nightmare will not come back.. It works.
There are lots of changes going on in his home and he is not the total attention of the household (how did this happen?) so he is not used to not being served, observed and complimented every moment.
Mom is tired, cannot pick him up, maybe cannot play outside as much as son wants, so maybe dad needs to step up and take son outside EVERY TIME he gets the chance. May Aunts, Uncles, Grandparents?/ Maybe hire a moms helper to take him outside while you rest inside? Son needs to be able to run and play extremely active for long periods of time (1hour to 1 1/2 hours 2 times a day. .. this will continue from now on. Son has a lot of energy in that body and if he cannot get rid of it whining, crying and tantrums, will help get rid of that energy.
Just hang in there. Big life transitions are hard for grown ups, they can be down right scary for sone children.