Need help with bandgap reference circuit

Hi newbie here but I am trying to design a bandgap reference circuit in Cadence. I am using a 2-stage Miller compensated op-amp for my amplifier. I already managed to achieve a CTAT slope of -2mV/K and a PTAT slope of +2mV/K. Current and voltages in the two branches are equal. The only problem is the PTAT voltage range is from -750mV to about -400mV while my CTAT range is from 800mV to 450mV, which means if I add them up, I won't be able to cancel them out. Anyway I can fix this? I tried using the Banba circuit but the resistors that I added to the positive and negative input of the amplifiers made no difference. I tried some current mirror configurations and no luck with that.

Completely lost right now so any help is much appreciated. Thank you