If I might add a dissenting interpretation to the existing answers....I think a minor change in pronunciation might alleviate your concern.
Note that, in the other answers, your name is being converted to romanized Japanese as 'omaru.' The 'o' at the beginning of this pronunciation would be very short and not accented.
I live in the US, and the gents I've known named Omar have generally pronounced their name with a bit of an accent on the 'O' at the beginning. Personally, I would romanize this as 'oumaru,' where the 'u' really just indicates a slightly elongated 'long O' sound at the beginning.
If you find yourself at Google Translate again, you might try listening to the difference in pronunciation between おまる (omaru) and おうまる (oumaru). (Note that the difference is simply how quickly the 'o' sound is spoken.)
'Oumaru' is the name of a city in Japan, I believe. And according to the Japanese/English dictionary I use, it is also seen as a surname in Japan. oumaru defined on jisho.org
Therefore, I'd suggest that, with a slight modification to how you pronounce your name, you can diffuse any misinterpretations. ^-^
Also, in the interest of full disclosure, I'm probably one of the ~less~ fluent people on this site. So if anyone strongly disagrees with what I say, I'd suggest you take their word over mine. (-.-);