Vauxhall Tigra Oil Pump Problems

hi there I have recently brought a 1999 1.4 16v tigra just done a part service oil/filters /plugs ect ect.its been running fine but for some reason the oil light has been showing and this is promptly followed by what seem to be the top end...

The oil light on my Tiggy has started coming on when the car idles goes out with when running. Also has started running hot when stationary i.e traffic lights. oil levels checked and okay - any suggestions please. Can car be used? Thanks ...