mind and body one step behind/feeling unsafe/insecure

while pondering a few posts today it seems that alot of you feel as though your body and mind feels as though its one step behind,this is typical dp for me and it takes up an enormous amount of my time and mental energy...but does anyone else feel as though the further they venture away from home the more unreal and unsafe they feel ?
what actually causes this,i would have thought that by now i would be able to deal with this symptom but it is so debilitating...its a feeling of being a 3 year old child and yer mum leaving you on youre on ina busy shop etc...