You've committed no sin with saying that, don't worry.
Islam strictly forbids killing oneself, hence the suicide bombing is strictly forbidden as well. It's even more forbidden than just killing oneself because most of the time suicide bombing results in deaths of innocent people around and the Qur'an says: "…if any one slew a person - unless it be for murder or for spreading mischief in the land - it would be as if he slew the whole people: and if any one saved a life, it would be as if he saved the life of the whole people.” (5:32)
Here are a couple of extracts from a fatwa "Defending the Transgressed by Censuring the Reckless against the Killing of Civilians" by Shaykh Muhammad Afifi al-Akiti:
"Fasl III. The Method: Maqtûl bih
The proposition: "attacks such as the September 11th Hijackings is a viable option in jihâd," where such attacks employ tactics - analogous to the Japanese "kamikaze" missions during the Second World War - that have been described variously as self-sacrificing or martyrdom or suicide missions. There is no question among scholars, and there is no khilâf on this this question by any qâdî, muftî or faqîh, that this proposition and those who accept it are without doubt breaching the scholarly consensus [mukhâlifun li-l-ijmâ'] of the Muslims since it resulted in the killing of non-combatants; moreover, the proposition is an attempt to legitimize the killing of indisputable non-combatants.
As for the kamikaze method and tactic in which it was carried out, there is a difference of opinion with some jurists as to whether or not it constitutes suicide, which is not only Haram but also cursed. In this, there are further details. (Note that in all of the following cases, it is already assumed that the target is legitimate - i.e., a valid military target - and that the action is carried out during a valid war when there is no ceasefire [fi hâl al-harb wa-lâ l-hudnata fihi], just as with the actual circumstance of the Japanese kamikaze attacks.)
Tafsîl I: If the attack involves a bomb placed on the body or placed so close to the bomber that when the bomber detonates it the bomber is certain [yaqîn] to die, then the More Correct Position [Qawl Asahh] according to us is that it does constitute suicide. This is because the bomber, being also the maqtûl [the one killed], is unquestionably the same as the qâtil [the immediate and active agent that kills] = qâtil nafsah [self-killing, i.e. suicide].
Furu': If the attack involves a bomb (such as the lobbing of a grenade and the like), but the attacker thinks that when it is detonated , it is uncertain [zann] whether he will die in the process or survive the attack, then the Correct Position [Qawl Sahîh] is that this does not constitute suicide, and were he to die in this selfless act, he becomes what we properly call a martyr or hero [shahîd]. This is because the attacker, were he to die, is not the active, willing agent of his own death, since the qâtil is probably someone else."
"Yes, we will naturally feel the pain when any of our brothers and sisters die unjustly anywhere when their deaths have been caused directly by non-Muslims, but it must be the more painful for us when they die in Iraq, for example, when their deaths are caused directly by the self-destroying/martyrdom/suicide missions carried out by one of our own. On tafakkur, the second pain should make us realize that missions of this sort, when the means and the legal particulars are all wrong - by scripture and reason - are not only a scourge for our non-Muslim neighbours but a plague and great fitna for this mercied Umma, and desire insâf so that out of maslaha and the general good, it must be stopped."
The whole fatwa can be read here: http://www.livingislam.org/maa/dcmm_e.html