Welcome to the Wefugees Community and thank you for reaching out to us. From my experience, procedures at the immigration office (Ausländerbehörde) can take some time - you should not worry immediately.
If you are getting too nervous, you may contact the civil servant or department responsible for you there via email, for instance. Usually you find the respective email address on their letters/invitations. Also always make sure that they have your valid contact details allowing them to reach you in case they require additional documents etc.
If you are not able to get in touch with them, you may contact a migration counselling office for support.
Please let us know if you need help finding one in your area.
All the best,