alternator no charge unless high RPM, guages flutter
 

Ok so i start my truck this moring, oil pressure pegged out before it even normally reaches normal range and stays really high, brake and anti lock light stay on for a few minutes after starting, battery was down all the way to 8 instead of 14. Temp guage fluttered before it was even off cold and still does, jumps fom normal range to hot all the time. Battery guage still flutters at 8 idleing but holds steady at 14 when in high rpms and seems to charge fine then. All lighs are real dim unless high rpm. i think alternator is the culprit. any ideas to this mess?