Hi hannaleejo,
Thanks for using Apple Support Communities. We understand that Instagram isn't working as expected. We're happy to provide some information to help.
It sounds like you've worked through some of the steps in the resource below already, so great job there. We do want to make sure nothing is missed, so please give those steps a second look.
If an app unexpectedly quits, stops responding, or won't open
If this continues after those steps, and it's only happening with Instagram the next step would be to connect with the app developer. You can see how here: How to contact an app developer
Thanks.