Why i cant open my instagram?

Last night i logged out my instagram from my friend ipad because she wanted to use hers. After that i logged in mine again and it couldnt open. It was blank then it crashed and it suddenly its expelled back to the home page. I thought its because of the app. I then asked my friend to use hers but she could log in hers. I tried my moms account and so did hers. I tried to log in my account on my phone and same thing happened. I tried with my friends phone but its still same. I tried to change the password, its changed on website but when i use app its still like that. I wonder what happen and how do i fix it? My ex used my account on his phone when we were still together. Idk has he logged it out or not. Do you think he might do something on my account that caused this problem on my ig? Please help!

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