Prusa i3 bed levelling issue

Hello!, I recently ran into an issue where my printer doesn't want to print on the bed, but print about 2-3mm above it.

Well to go into more detail, I was have installed a auto bed inductive sensor and before each print it (after heating up bed and hot-end) would normally run the G28 command . After that finished it would end up in the sensor in the middle of the bed, as it should. Then it runs the G29 command and it probes all four corners and before it starts printing it raises about 2-3mm and starts extruding the plastic in mid air. I thought it was an error in in marling firmware so I checked my code in the "config.h" file in marlin and nothing seems out of place in the auto-bed levelling section. so I don't know why this is happening. I tried to find the source to the problem but no luck...

Funny thing is that this started randomly as I usually print using an SD card.
Any help would be much appreciated .
Thanks