So I am just outside of Diamond City, and I must've accidentally harmed a DC guard.. I know I did kill a few outside of Diamond City as they were shooting at me! And now I cant get in with out getting shot... What can I do to fix this? Help please.

reload before you got shot?

(or go back to Sanctuary Hills and wait at least 72 hours)

Thanks I'll try that.. Basically go home and sleep for 72 hours then fast travel back.. Correct?