hi Vikky
Relooking at your project, just consider a compression load at first.
The L/C is rated at 1.6mV/V for a 50lbs load.
The Vext= 4Vdc so for 50lbs that would be 6.4mV output from the L/C.
Your working range is 20N, say 5lbs, so the bridge output for +20N would be 640uV.
You need to raise this to 500mV from the INA326, thats a Gain of 781.
The same calculations apply for a tensile load of 20N.
ie: -640uV raised to -500mV, still a Gain of 781.
Without offset the output from the bridge, between -20N and +20N would be 1280uV 'change' * 781= 1000mV
As you are using a single supply for the INA326 the -500mV cannot be achieved so you have an Voffset at +600mV.
This offset shifts the output swing of the INA326 to +100mV thru +1100mV, with a dc centre point of +600mV.
Summary: for a INA326 Gain of approx 780, the RG resistor is 2K and the R2/C2 combination is approx 750K and 150nF.
These calculations show that your trial values of Rg of 4k5 and 8k and the R2 at 2MR are well outside of specification.
OK.