I've been working on building a circuit which uses a wheatstone bridge to find the value of a resistance temperature sensor (Danfoss AKS 21) and then passes that to a differential amplifier the output of which is to be read by an ADC.
When I read the voltage across the bridge with a multimeter without the op-amp circuit connected, I get values that I expect (at room temp around 0.87V). However, when I connect the circuit to the op amp, the voltage across the bridge drops to around 0.5 V.
I've included a schematic I made of the circuit below. Would really appreciate some help figuring out where I'm going wrong.
I'm using the same 3.3 VCC to power the op-amp as the rest of the circuit.
Thanks in advance everyone, Al 
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