Glad you found the board. I have a history of microcalcifications in my left breast. Because they have not clustered I have been advised to continue with the 6 month mammos for a while longer. If there is a cluster then they will be able to biopsy and get answers for you. Like Bev told you, heavy microcalcifications can be a precursor to cancer so get those check-ups and follow your doctor recommendations.
The procedure is not awful. I did have some local anaesthetic to numb the site and I did not received any sedative. I do not like valium, it gives me a terrible hang over, but then I really didn't need anything for anxiety. I was very calm through all of my tests needed to make a definite dx. Some people thought I was strange, but I was thankful. If you are suffering from a lot of anxiety, then you should ask for something to help you through the test.
Good luck and let us know what happens.