Sex after baby!

Hi all! I am 2 months postpartum and I finally had sex this past Saturday. It hurt so bad!!!! It feels like my vagina is half the size it used to be. I could hardly fit my vibrator in there let alone my man's baby maker. What happened to me?!?! Plus even though I was super clean and careful it feels like I already have a yeast infection. Is this normal??? Is it supposed to hurt the first time? Anyway to help this feel better?!? I had a vaginal birth with minor tearing