Babies cry. It's OK. Baby wearing is nice for people who can manage it, but i's also OK to put your baby down. All my kids went through this phase. You do what you need to do. You hold hold hold and love love love them, and when you need to put them down: you do. If they cry, they cry. They WILL LEARN, that its actually OK to be put down, and will start to feel secure being put down if you just let them work through it. WHATEVER you do, you do not want to train them to get SUPER frantic in order for you to pick them up. They learn this when you put them down, but then cave and pick them up when they are super frantic.
You need to know yourself: Will you cave and pick him up? Or will you have the capability to let him cry for ten minutes and pick him back up when he's quiet, or let him sleep? Both answers are OK, there is no right or wrong, but you need to set habits, so figure yourself out and act accordingly.
If you WILL CAVE and pick him up, then just wear him and never put him down, and pick him up the minute he cries and sleep with him so that it's on YOUR TERMS until he's a bit older.
If you CAN BEAR the crying? Then stick to your guns. Give lots of love and holding, but when you put him down: Leave him down for 20 minutes while you wipe down the kitchen. Even if he screams. He will learn that screaming doesn't make you pick him up. That may not stop him from screaming, but he won't be afraid. He'll get used to it. Same with whatever bed he sleeps in. Children adapt to whatever routine YOU GIVE THEM. But you have to stick to it in a guilt-free, confident way. And you have to accept that babies cry. When my third was born, and I was home alone, never putting her down wasn't even an option with two other small kids and a whole house to run. Sometimes she howled, but she's a healthy 5 year old now.
In lots of cases, you can stave off crying by letting your baby be in command, but it leads to lots more crying later if that parenting style continues and 2 and three year olds can still get their way by crying. At 3 months old, you still have some time decide to figure out your style.