The more we connect back to our body, the more we can feel in tune with it to know what feels right.
In clinic, the most common side effect I see with the oral contraceptive pill (OCP) in women using it is depression. The OCP depletes an array of vital nutrients our body requires including B12, B6, folate and can even cause sensitivity to histamine (allergies). Adequate B12, B6 and folate levels are vital for neurotransmitters to work correctly. Women who carry the MTHFR gene such as C677T Homozygous who naturally have low folate absorption, and women with low B12 such as vegans/vegetarians or women who carry a TCN2 polymorphism meaning they cannot absorb sufficient levels of B12 are examples of women particularly at risk of depression.
Here is an interesting paper below evidencing the depletions of the OCP.