Are there any names that your family used to call you when you were younger? This may be a good option and bring back good memories at the same time.
You can also research what your name means or is similar to in other cultures. If you find one you like you can go from there.
There has to be a personal connection to some type of nickname. It should arise from some type of story, trait, or family/ friend experience. Nicknames works best when they are driven from some type of personal story. It seems to me that the best nicknames have an inside joke or some type of story behind them which lends credence to both the name and the people who use it. It is going to be difficult for a name to be generated outside of this setting that is going to be authentic and meaningful. I would also suggest that the best nicknames happen naturally, organically, and sometimes without the forcing element.
My suggestion, because my background is in multicultural ed and such, is that you find your family ancestry, identify the main ancient language your ancestors spoke, and search for a title in that language such as "Princess", "Doctor" "Professor", "Magician", "Mistress" or whatever, and just go by it. Then, let people figure it out. It is always so rewarding to feel like you know something smart than people have to research in order to understand it.
Another things are prefixes and sufixes. When I teach Spanish, all my students suddenly have the suffix INO after their names (meaning "younger") so even Joseph- is Josephino, Jamal is Jamalino, and so forth. They love it. You may want to try something curious like that.
Your name should be according to your liking first, then you should bother about others. You need to consider some issues like culture, family, religion, nationality etc. But, your liking should get the topmost priority.
Your name sounds as if you are Muslim. I may be wrong. But, in case you are a Muslim, you can shorten the name and make it Maria. Yes, Mary is also a nice name. You can use Mary also if you wish. Spell the name loudly whichever you like; then pick that one which sounds best to your ears. OK?
Just Mary. It's a beautiful name with a special resonance.
This is an unusual question. In order to have a nickname that would work for you it is important to know facts about you. I would recommend that you sit down and write out some things about yourself.
What do you like to do?
Are there any unique things about your culture that you like?
What nicknames do you dislike?
What are you really good at?
What words are relative to your personality?
How would your friends describe you?
How would you describe yourself?
Take these things and then look up some names that could go with them. Beware of getting stuck with a nickname that you might outgrow.
Years ago I had the nickname Bohemian Hippie. I was a hippie chick then and made candles, love beads, and handmade dolls for a living. I am now a social worker and a school teacher. I am not so sure that I fit my nickname anymore, but I still use the name.
On the other hand there are cultural nicknames. Mine is Katerieneschen.' My grandmother always called me that and it means little Kathy. My children have been less fortunate, one has the nickname "Bean" and the other has the nickname "Boo Radley." I even have one whose Jewish great-grandmother, my mother, calls him "Da Bobbie." He is 37 now and she is the only one who gets away with that.