My strength has dropped from 4 or 5 to two over the last few nights of playing and I'm not really sure why, anyone know??

Anyone

Check the effects tab on your Pip-Boy. You may be addicted to a chem or something and suffering withdrawal.

Yeah it says I have a psycho and buffout addiction but I have had them for a long time how long do they last I used them like twice

Addiction lasts until you cure it at a doctor, or by using the aid-category item Addictol.