2DPO ....

Desiree • I have a beautiful 7 year old boy from a previous marriage. I am now remarried and my husband and are TTC :-)
I believe I'm 2DPO I have a few questions: 
1) Has anyone felt a heaviness in their lower abdomen and sore boobs/nipples this early? Plus, pretty emotional/sensitive.
2) Hubby and I are still very frisky feeling. Would it be any harm to possible implantation or fertilization if we were to have sex tonight?