SSD1306 screen causes distortions in ADC

Hi! This is my first post here and if I make spelling mistakes please point it out. I'm working on a project that uses Arduino Nano and it reads analog values and prints it on a SSD1306 based OLED screen. I made a voltage divider with 2 10Kohm resistors and connected the output to A0 pin of the Arduino Nano. I connected a pulldown resistor to A0 pin to remove noise. It reads fine when printing the values to serial but when I connect a SSD1306 screen sometimes it reads 40 to 150 when nothings connected. Can I fix this problem or do I need to use an external ADC? I'm using the SSD1306AsciiAvrI2C library instead of Adafruit SSD1306 library because it uses too much SRAM.