Don't freak out kid. Loosing the baby teeth at 19 is not a big problem, it can be seen in few cases, but the good thing is that if the space is created due to the tooth loss
can be fixed. First thing you should do is go for an OPG radio graph, which will help your dentist
in diagnosing the problem. Sometimes tooth gets impacted or get stuck under your milk tooth and fails to erupt, in this case with the help of orthodontic treatment and minor surgical procedure we can make it erupt. But if the tooth is not formed we can go for implant or bridge depending on the condition.
So don't worry at all and consult your nearest dentist and take advice.
May the joy be with you.