Hi Becky, had this happen to someone else last fall.
Go to your GEDCOMs Page and click on the GEDCOM file name you loaded in May. If the GEDCOMpare Report appears with no names follow Mindy's suggestion, something is stuck in the system. If names appear, was your name and data in the GEDCOM file you ran through GEDCOMpare? If no, follow Mindy's suggestion.
If yes, we may have a fix.
If you Accepted a Suggested Match to your present Profile you have 2 possible Options.
First: Click on the Compare button on the row where you name appears and select Remove Match and follow the instructions.
Second: Click on the Compare button on the row where you name appears and select Edit and complete the import. Here you can choose not to add any data from the GEDCOM file and or delete what you don't want imported in the text edit box. You will still have to probably do some work on the Profile after this to clean it up. GEDCOMpare imports have a tendency to mash the data and sources.
Now I am not sure when using either option if the system is updated immediately, I believe this is the case, or if this is done by a system maintenance routine run sometime during the night. If you still cannot merge immediately after performing either of the above options, wait 24 hours and try again.
If after 24 hours you still cannot merge, follow Mindy's suggestion. ;)