I see you like teddies, I make up stories with my Cuddly toys. Peter the Rabit and Rex the dog. They are the best of freands, and the go off on Adventures. Becouse they have to keep everything's safe.
Also you could teach your teddies a new dance. Put some music on and go for it.
Do worry I sour someoun will put it on YouTube for you. Just dance and sing along to you toys like you just don't care and have fun.
Ugh, I know how upsetting that feeling can be. Its weird since wearing a diaper and being little is supposed to make you feel more happy and free, but then you get sad because it isn't quite enough yet.
Well, they say you should go out on a walk when you are depressed, so that is probably an important thing to do. Take a walk, even with your diaper under your pants (which can actually be pretty fun).
Make sure you have eaten well, sometimes you can get feeling down if your body is low on energy, same with water.
Watch some new fun cartoon to help distract you, make you regress some, and just relax. May I suggest a few:
My little pony is a really cheerful show, also on netflix
Adventure time is entertaining and weird, not sure how you can find it.
Fairy Tale is pretty awesome, i've been getting way into that, and it is a good kids show.
Listen to music, if you want to feel regressed but not bored of it, try Rockabye Baby, rock music put to lullabies.
Unfortunately, buying things helps me get a little exited too, but that is a bad habit to get into. If you must though, maybe go to walmart or the second hand store, look for a cute new stuffed animal, a pacifier, maybe a baby bottle if you don't have one already.