Help !!!!!! Tmi post

Hey everyone so I have a couple of quick questions ...... I'love be 6 months pregnant on Wednesday with my first baby ( a little girl ) me and my husband are both overjoyed.... However in the last week I've been having some stomach pains not your normal pregnancy pains ... For two days I had extremely runny diarrhea and then it stopped well today I've only pooped once and when I did it was black I've never had this before ever .... Has anyone else had this happen them to them ? I have bad anxiety so I'm trying not to freak myself out but I want to keep my little girl safe ..... Any advice .... I go to my obgyn on the 10th so I'm trying to wait to go until then but if it's not safe I make change my appointment to a sooner date