Ford1994351w

Hi my f150 has started to start really hard it feels weird like somethings off plus the when the truck warms up to around 160 to 185 degrees it starts having 20lbs of oil pressure but it will go back up to 40 or 50 lbs when I start to drive and cruise down the road should I be worried. I do plan on changing the oil in the next day or two I'm not sure if that will help me out thanks for the help