Breastmilk drying up??

So I'm about 5 weeks pregnant, and I think my breastmilk is drying up?? Is that possible? My first born is 11 months old and I can tell she's not getting enough while eating. She's crying and constantly switching breasts to find more milk. This is all recent 😭😭 Is this possible? Has this happened to anyone else?? Please help.