My LO is six months old and EBF. Due to insurance issues, I haven't been able to pick up my birth…

My LO is six months old and EBF. Due to insurance issues, I haven't been able to pick up my birth control. The depo shot was what I had one time after complications from an IUD. It was three months since the shot at the end of November. It did not play nice with my mental health so I'm switching to the mini pill. In the meantime, we haven't been using condoms since I heard it usually takes an extra month to get out of your system plus I'm nursing (he's not on real food yet). This past week I've noticed a lot of nausea in he evenings and just not feeling well. I never really noticed early pregnancy symptoms with Joshua since I knew I was pregnant before I had any. Is it more likely that I'm pregnant or just sick? I had a negative pregnancy text at the dr November 28 before getting the mini pill. My period hasn't returned yet either.