2002 Chevrolet Trailblazer 02 oil and cluster issue

My 02 trailblazer has several issues, 1.) My change engine oil light is on but I haven't reached 3000 and the other day I started it and it said that the oil pressure was 0 but when I stepped on the gas the pressure would go up but it would lower again when I released.I shouldn't need an oil change yet as I've only put a little over 2000 miles on the oil that's in it. I've checked the level and its full. I haven't heard any unusual noises coming from it like knocking or ticking that i'm aware of and it isn't leaking. 2.) My speedometer cluster hasn't been registering the correct speed. Sometimes it will move up a little bit when i'm driving but the speed isn't correct, it mostly stays at 0 now. It started doing this last year but it only does this when it is cold but last year it would correct itself after a little bit so it wasn't to much of a concern last year but now doesn't even correct itself. My tachometer hasn't been working at all for about 2 years now.