Is it true that if you commit suicide, you won't go to heaven? But if there is no Jewish hell, where will you go?
I hope the reason you are asking about suicide has nothing whatsoever to do with your current state of mind or circumstances in real life. It's not a pleasant issue to be thinking about.
You write that there is no Jewish hell. Well, not exactly true. If you've ever overstuffed yourself at a Jewish simchah, the night after was certainly a form of Jewish hell. Aside from that, we find a place called Gehinom mentioned in the Bible and discussed at length in the Talmud and many classic Jewish works. Think of it as a sort of laundromat to clean up souls that have been soiled in their passage through this world. Once sparkling clean, they can continue up to their spiritual place from whence they originated, and even higher.
A soul that was involved in a serious crime, such as homicide, G‑d forbid, needs a heavy-duty wash to get back in shape. Suicide is considered just the same as any homicide—your life doesn't belong to you any more than anyone else's life belongs to you. All life belongs to the Giver of Life—and He doesn't appreciate life being destroyed wantonly.
Nevertheless, there are those who commit suicide out of extreme distress and emotional agony. Then it's left up to the Knower of All Souls (same one as the Giver of Life, a.k.a. G‑d) to know whether this person really had any free choice left in his soul. According to that knowledge will be the clean up afforded that soul.
We have a lot of answers, essays and audio classes on the Jewish understanding of hell listed here.