If it hits you, you'll know it. For me it was horrible Depression and crying for no reason, like your worst PMS times a million. Be on the look out for suicidal thoughts, too. If you know ahead of time that you may have some crazy symptoms, it helps you deal with them a little better when and if they do come, so you don't just think you're going crazy. Good luck :)

for me the crash did not happen until period #3 after removal. my symptoms came back when i had my period, but the symptoms were not as extreme as when i had mirena. my symptoms went away again.