I am like clock work on my period my whole life the only time I missed my period was with my first…

I am like clock work on my period my whole life the only time I missed my period was with my first daughter and I just missed mine this week. but I also took a home test came out negative so I was discouraged I'm going to the dr tomorrow but when I went for my daughter they did a urine test how do I get them to do a blood work one? I'm also really nipple sensitive and I'm cramping but I'm constantly checking to see if I'm bleeding and I'm not. I'm extremely nervous for tomorrow I really want to keep positive but what if I'm heart broken ?