Bism Allah wa as salaamu alaykum.
Something in human nature causes us to turn to others for reassurance and confidence building. We seek approval for our clothes, hairstyles, weight, body shape and fitness, home decor, choice of car, etc. We want others to find us attractive, to think we are good, nice, funny, kind, generous...the list can go on and on. We want our spouses to "want" us, to be pleased with us and to show pleasure in us.
So what happens if the world around us doesn't give us what we want? What happens if we don't get others' approval for our bodies, material choices, or personalities? We find ourselves depressed, miserable, feeling unwanted, without confidence. We let other people, other imperfect human beings, affect how we view ourselves. We let other people's opinions determine whether we are satisfied or not with ourselves.
Subhaan Allah! Who is the One to Judge us? Who is the One who created us as we are? Who is the One we need to please? Other people's opinions, praise, or criticism will not earn Allah's Pleasure. Other people's opinions will not add weight to our scale of good deeds. Confidence lies in one thing. This is an importance sentence so please, take it very slowly and seriously.
Confidence lies in knowing you are submitting to Allah's Will and striving to obey His Command in every aspect of your life.
Confidence lies in knowing you are taking care of yourself and dressing yourself as Allah has decreed and as the Prophet Muhammad, salla Allahu alayhi wa sallam has modeled for us in his Sunnah. Confidence comes from knowing that on any given day you are up to date with your prayers, your fasting, your zakat, are striving in some way to perform Hajj, and are basing your life on tawheed - belief in the Oneness and Perfection of Allah.
Will you continue to worry about others, when if you follow the Quran and the Sunnah you will be doing all that is praiseworthy and best? Will you continue to worry if you know that your Creator is pleased with you?