4runnerfanatic95

alrite i have a 95 4runner that i just put a new rebuilt engine in a few months ago, the past few weeks its been leaking oil and has been in and out of the shop, first it was the valves, a gasket and something else, and it stopped leaking for a bit but then it just started again, i keep adding oil whenever it gets low but it cant be too good.. the real problem though is now my oil pressure is almost as low as it can go. normaly it used to be in the middle but now when i start it up it goes where it used to be but once i get moving it drops like a rock and sometimes goes up a little to maybe a quarter if that, but not alot, and doesnt really move much. has anyone else had this problem or know what it could be? could i have a bad oil pump? thanks