It's easy to lose one's confidence suffering Parkinson's or any serious illness. When first diagnosed I came across several people who'd been living with Parkinson's for some years and were already experienced with the many symptoms and problems that occur as the disease advances. One particular change puzzled me, which appeared to be a lack of self esteem and confidence. Many people with Parkinson's stop socializing and going out. The huge change is noticeable, when someone might originally have been very sociable and the life and soul of the party.
Speaking from experience, I can now understand how losing one's confidence and retreating from the world can happen. I have written before about losing one's voice, sounding hoarse, speaking quietly, along with a monotone and slow speech. This would without doubt make anyone cautious of speaking when amongst others, causing complications with socializing. It's not surprising that a Parkinson's patient who once might have been vivacious and talkative, suddenly will sit quietly like a wall flower.
One's physical appearance can make one lose confidence. The shuffling when walking, hunched shoulders, a stiffness and rigidity of movements, all make one self conscious and uncomfortable entering a room a room full of strangers. If people are unfamiliar with Parkinson's, they will not realise what is wrong, and sadly through lack of empathy or understanding, as if one is contagious, they will keep their distance. This is hurtful and enough to discourage any Parkinson's sufferer from venturing out.
Eating in company is another problem; the thought of dropping food, making a mess, and taking longer to eat than anyone else, unfortunately aid losing confidence.I am in this very situation myself, and I do not have an answer for you. All I can do is tackle each day at a time and do the best I can.