my Outlook and office 365 keep shutting down

I recently upgraded to office 365. My daily job is highly dependent upon using Outlook. Almost every time I click on reply or forward an e-mail, Outlook is shuts down, it stops responding. You don't know how frustrating it is to be typing e-mail, and the Outlook is shuts down losing all the stuff I just typed. The other issue is that to complete a simple task takes three times as long as it should.