My Body is going crazy

I have been trying for a year and half. And this weekend I started spotting only when I used the toilet sometimes. I did have left side pain off an on all Saturday. But I still had a week to go before my cycle started. Was going to take my day 21 test on Monday.My back stopped hurting and I was feeling like my self. Then on Sunday my back started to hurt and then Monday I started to get nauseous that I threw up that night and Tuesday night. I took a hpt on Monday and it was negative. Now I don't know if that was just implantation bleeding and pain or what. And my nipples are starting to tingle and come to a point and I have diarrhea to