I feel that it may be two part. One is that he is trying to deal with the change in his pack. He just needs some time to sort things out. The second is that he is sensing your feelings and is trying to protect, comfort, guard, care for you.
I would start with verbally confirming to him that ya'll are fine, things are different but you are happier now and that he is safe. Neither you or he are going anywhere. The goal here is that he must be invited onto your lap. Start by telling him no when you sit down and he tries to sit on you. Moving him off of your lap and try to get him to just lie beside you, touching still, but just not on your lap. You will probably have to pick him up and place him beside you several times, but just keep at it. Then if he'll lay there even if just for a moment at first, praise him, maybe give him a small treat, and then YOU pick him up and place him in your lap. When you get up, pick him up off your lap, place him on the couch, tell him you will be right back and then go do what you need to. The same would go for him sitting on your feet. Tell him no, pick him up place him on the floor. Calm, firm, quiet voice. It will take some time...come here to yell if you need to
but keep after it and he'll get better as he feels better about his new environment.
Don't ask me how to get him to not follow you from room to room tho. I've never been able to get mine to understand, I'll be right back, I'm not going anywhere, you can stay here. What I've found is that only with age does it not become necessary to follow me everywhere.
Good Luck.