Effexor - breast pain?

Hi there - so my dr upped my Effexor dosage after my last panic episode a few weeks ago and I have been feeling a lot better. However I got my period 2 weeks ago and what usually lasted 2 days instead lasted almost 2 weeks. It finally stopped 2 days ago BUT ever since it stopped I have been having horrible breast pain. Of course I have convinced myself that it is breast cancer and the panic attacks are trying to return. Im trying not to let my panic take over but it is so hard. My mother happened to look up Effexor and breast pain and found it to be a side effect (though not common) as well as abnormal spotting. Has anyone out there who's on Effexor ever experienced anything like this? also if you have is this something that goes away over time once my body has fully adjusted to the dosage increase? Thank u