pregnancy symptoms

I was wondering when pregnancy symptoms can start? 

I used to be on the nexplanon (bar implant birth control) from june'16-Jan 11, 2017 and had my period from December 28th-January 14th. I believe I had ovulated about a week after the removal of the birth control. My boyfriend and I have been having unprotected sex (he pulls out) and I believe I might be pregnant. Would it be possible to feel symptoms this early? I don't know if it's withdrawal of the birth control that's causing dizziness when I workout (which I never used to have) , sore nipples, cramps that feel like contractions (for the past two days), increase of anxiety. 

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