After a quick look at your design,:
I'm not sure why you are using 2 MOSFETS. I Would recommend using a single one and to limit the current you should control the width of the pulse
applied to the gate of the MOSFET instead of the voltage level. So use a comparator instead of an opamp. For a reference of current mode control you should take a look at the internal diagram of an UC3845. That will give you an idea on how to implement cycle by cycle current mode control. Hope that helps!