Why is my baby doing this?! Arghhhhh

[Arghhjhgd]

Ds is 10 months. In the last week he’s become so so so clingy. Cries if I leave the room. Cries if I get out of the playpen. Cries if I go and make a tea. He was never like this. He was quite happy to play alone for a few mins, even half an hour sometimes and I would be doing jobs. I am ashamed to say I’ve left him in the play pen to come and type this as I can’t cope with the crying. It’s literally non stop the moment I move?! I am hating it. It’s making me want to be back at work ASAP. How can I stop this?!

Unfortunately it’s totally normal and most babies and toddlers go through this at various points (sometimes more than once!)
All you can do is ride the wave.

It's one of those milestones where you grit your teeth and power through. Your baby has become aware of their surroundings and is able to see you in it. They already "know" you are food, drink and comforter so they get upset when you disappear (as they don't understand you are coming back). It's also the time you push other adults forward to do feed, nappy and comforts so baby sees a lot of adults and not just mum as the all-powerful, all giving one. Plus you need the break!!

It's separation anxiety.
You've been their number one from the get go and now they are a little more able to amuse themselves, they are still looking for the reassurance from you.

My advice would be to set aside a week (maximum) that you would try to sort this out.

For the first time you leave them, go out of the room with the doors open and them in the playpen but keep chatting away to them for about a minute or two. Go back into the room and settle them, give them a dummy or a toy and tell them that mummy has to go to the kitchen to wash some dishes but they would be back in a minute. Keep talking to them.
Repeat.
Next time, go out of the room for 5-7 minutes, keep chatting to them all the while and if they are crying, return to the room, get them settled and leave again.
You'll get your step count up in no time!
Repeat.
Go to the loo for a few minutes (leave the doors open, so long as there isn't anyone else in the house) keep chatting away about nonsense and anything. Return to the room.
Each time you go away for a few more minutes than the previous time.
By the end of the week, you'll be able to leave the room for about 25 minutes or longer. You want to be able to do a chore or two while they are occupying their own time with their toys.
You might also get away with putting a radio on in the kitchen (one that does talk radio) or playing an ebook over a smart speaker and before you know it they will be better than ever!

It takes time and perseverance!

What you describe is completely normal behaviour in babies of that age. Whenever you're out of his view, he'll cry. When you're doing something in one room, take him with you but put him in the playpen there, or put a safety gate at the doorway so that he can still see you. Yes, it's a pain, but this phase will pass.

It's a developmental stage. Part of him learning that you are a separate person who can leave but who also comes back.

You will be back at work soon OP. This too shall pass.