iphone SE changed to "save battery life" with black text in a white background only in apple aps. Inverting colours and colour filters does not work

Hi guys, trying to save by battery on my SE phone an option came up to change the app backgrounds to black. So did it but don't like it. Have tried the colour filters which are off, have tried classic invert, which works but it just makes all my apps a funny colour. Have rebooted - no joy. The black background, white text is just in all the apple products. Help????