I'm so scared I'm pregnant again 😬😬😬😬advice please

My husband and I have a 5 month old. We definitely did not plan to have more children since this is our 5 month old is our 3rd. I was just about to schedule for a birth control appt but we also have not been safe with sex which is our own fault. I do not know how to tell him without him freaking out at me?! Help me please!Â