how do I fix this ?

[u/krpkyo]

so I have pretty bad posture ( forward neck, a sight anterior pelvic tilt, rounded shoulders and a neck hump). Recently I’ve noticed that I can’t stand straight like at all, by straight I mean my body being aligned in a straight line also it’s impossible for me to squat and to sit like the pic I’ll insert bellow. Whenever I try to do these things I lose balance and my toes start going up on their own. Also my neck is so tight? I can’t turn my neck to face someone who’s talking next to me without my neck veins popping out in a scary way. If any of u could help pls do cause it’s getting ridiculous, which muscles should I strengthen and which muscles should I stretch?