Thank you for reaching out to our community and for contributing with your question :-)
I'm very sorry to hear that you had such a hard time dealing with your case and the living situation.
Regarding your question if you can withdraw your case, Thorgen gave a very detailed and helpful answer before. Please have a look: How do I stop my asylum process in Germany?
In his answer, Thorgen lists a few services provided by the German government for people who want to voluntarily return to their home country, or move to another country that would take them.
Please note: If you withdraw your asylum case, you don't have any legal status in Germany and would therefore be asked to leave the country.
There are options to return to Germany (as no entry ban would have been imposed on you, when you return voluntarily instead of being deported) on a tourist or student visa. This Germany Visa website explains what you need to know about student visas: https://www.germany-visa.org/student-visa/
If you return on a visa, you should be able to apply for asylum again. Please have a look at the following thread, where this option ("Folgeantrag") is explained and why you need to be aware of the Dublin-III Regulations:
Does fingerprint in BAMF has negative effect for Schengen visa in the future?
Here is information from the BAMF regarding follow-up applications: http://www.bamf.de/EN/Fluechtlingsschutz/ErstFolgeantraege/erstfolgeantraege-node.html
Furthermore, here is some information on what happens during an appeal and your chances:
I got rejected and appealed in court - What are my chances to stay in Germany?
If you haven't reached out to a refugee support service (refugee council of your area, for example) yet, going there may be helpful to discuss all of your options in person before you make a decision that affects your legal status!
I hope this information helps. Please reach out to us again if you have any more questions and take care.
All the best,