Dear @Coline*,
Welcome to the Wefugees Community and thank you for reaching out to us.
I highly recommend you to contact a refugee counselling office in the first place to get some individual support - for instance the so-called "Asylverfahrensberatung" (asylum procedure counselling). These offices work free of charge and confidential. They may also refer you (as helios mentioned) to a lawyer if needed.
The Dublin procedure is a quite complicated regulation. Handbook Germany provides a good overview at their website. I could not fully understand if the the "yellow letter" you received was the BAMF's decision already ("Bescheid") or just the protocol of the interview. However, until you receive the decision letter, there is no need to be afraid of deportation. In general, hiding is not a good idea as "the deadline for your potential Dublin transfer will be extended to 18 months. If you, for example, do not stay in your accommodation centre for over a week and the BAMF learns about it, they may assume that you have gone into hiding." (Handbook Germany).
Again, please reach out to a counselling office - I am sure they can help you with any action necessary now. Let us know if we can help you with the research for respective contact details (for this we may need you approximate location).
In any case, please also don't hesitate to get back to us with any further questions.
All the best,
Meike