You're not at all terrible with words, OP, you described both your inner and outer situations very well and it's clear you're suffering terribly. Tension of that level can't go on for too long before something in you breaks, and the coffee mug synchronistically illustrates and describes what's going on inside you at present. You feel unsupported in some essential way by your partner, that's a source of growing pressure because you simply don't know how to manage the anxieties that 'set you up to fail' in work situations, so you're understandably avoiding working that through. You're trying to be responsible for a special needs child which isn't straightforward and can often be unmanageable for parents without their own mental health difficulties. That's a considerable source of pressure, thinking about his needs and now feeling intense doubts about your decision to uproot him (and yourself). Incidentally, it's important to acknowledge that your partner agreed to this move too, and must own his part in it. Plus he's likely to be a factor in you feeling so unattractive, so there seems to be a relationship issue there that remains unresolved. But a third source of pressure now is your doubts about whether the friendship can withstand this living arrangement, as not only do you not want to lose the friendship but you're also depending on having enough time there to plan a constructive next step. All those pressures together are frightening you and creating a crippling sense of insecurity which any mere mortal would struggle with! Added to all that, you have a toddler to take care of, which can be a full time job in itself.
Is it possible your friend doesn't feel comfortable asking for your help with her baby because you're renting from her and she doesn't want to impose or make you feel obliged? Whatever's going on in that respect, it feels like you would both benefit at this stage from a gentle discussion about one another's expectations in the new arrangement, to check out how you're each feeling about things. Does she know about your struggle with anxiety and depression? If that's something you've ever been open about with her, could you find an opportunity soon to give her some insight into your fears about imposing or 'messing up' the friendship, explain that you're so worried about potentially cramping her style? Would she have invited you without understanding that it was likely to be a difficult transition for you, do you think?
Sorry, I realise that from the inside where you are what I've suggested might just seem overwhelmingly difficult to get into. But somehow or other, reaching out to her, and letting her know that she can also feel free to reach out to you, feel like important steps to take very soon. Is your partner talking to you, aware of how it all feels for you at the moment?