Littlespace is when you are actively expressing yourself throughout more childlike or childish displays and is more tied to a general mood in making this decision to express yourself so. You should not really ever be "stuck" in a situation where you can only express yourself as if you were a biological child. If you are "stuck" then perhaps it just means you need to work through more to help identify more of what is going on and what you are experiencing and/or feeling. Perhaps you are in the position where you don't quite know how to identify what you experiencing and are running to regression instead of facing the issue of investigating what is going on with your mental health.
So, I feel like perhaps you are clinging onto the mood of childlike expression ("regression") instead of working to resolve the root cause of issues you are facing and emotions you need to deal with more head-on. Perhaps it feels easier in some way to use your regression to self-express when it comes to negative emotions and stress, but perhaps you are using this regression option to avoid the actual issue(s) since it is somewhat personally distracting and places others in the role of resolving your problems for you. Nobody can resolve your issues but you though so at some point you will need to make some efforts to not only express your distress and unhappiness but actually take actions to make resolutions.
It isn't "wrong" to regress when you are feeling stressed out or unhappy, but it isn't healthy to rely on it as your sole way of self-expression because it is not productive to resolving your distressed mental state or underlying issue(s)/potential condition(s). You can't expect anyone to be able to help you feel better when you're just retreating to regression.
We need to remember that just because something feels therapeutic does not mean it can take the place of actual therapy with a professional who can help you resolve or minimize negatively impactful issues like anxiety. Do not fall into the mistake of believing that experiencing your littlespace is a "good coping mechanism". "Coping" is not "resolving", and is certainly not healthy growth in a positive direction. "Coping" can absolutely be detrimental to your long-term happiness. Sweeping real problems under the rug and saying you are "coping" is not realistically beneficial to you. Coping with cold weather by rubbing your hands together while standing in the middle of a winter snow storm of -15F may make your hands warm but will not stave off frostbite, you know? Coping can only go so far in giving you a small amount of temporary comfort, but it does not actually prevent or resolve the serious issue(s) that need to be acknowledged and taken seriously.
It sounds like, to me, you are struggling with a mental health condition such as depression or that you are experiencing some sort of stress you still need to work through and learn how to resolve or manage better. You may be completely unaware you are facing some issue(s), especially if you've been skirting around them by "coping" for a long while. I would strongly encourage you to find a therapist that you can talk to about feeling excessively sad or lonely to the point that you feel "stuck" only expressing yourself in childlike ways. If your first therapist doesn't understand and work to help you then try a different one until you find a good fit for you. Someone can and will help you if you take the steps to seek them out and let them know you're in need of some help.
My suggestion here would be:
- Explore various ways of relieving stress in your personal life. Search Google for some ideas of general stress relief and try them out in your day to day life and see how some of them make you feel.
- Talk with someone about your concerns, worries, stress, and general problems. Community forums can be great for letting things out. Chat rooms may be helpful. A good therapist is probably best since they can professionally help you work through things and have an educated background on psychology and mental welfare. Bottling your thoughts up isn't helpful though.