HELP! I think someone hacked into my Facebook, Instagram, and email accounts.?

[Jessica]

i opened my instagram and it said i needed to re-log in so i did. when i tried my password, it said it was incorrect. so i clicked the "send email to reset password" link thing and when i tried to open my google email account, it said it was wrong as well. i had it send a confirmation code to my phone and got into it. then when finally into it, i saw some emails confirming changed passwords to my email, instagram, and facebook that i HAD NOT changed. when i checked my facebook, the same thing happened when i tried to log into instagram. my facebook profile picture was changed to "i am a massive faggot" and it now said that i was in a civil union.
I reset all the passwords but i dont understand how someone got all my passwords. i dont ever share passwords so it doesnt make sence. any ideas?