.May I ask why it is that Muslims reject Jesus as the Messiah and as God?
We accept him as the Messiah. We reject him as God because we believe that he was a human Prophet sent to the Jews to call on them to return to the proper practice of their religion. We also do not accept that God manifests himself on Earth.
This confuses me.

I was once presented with some information that said men treated women like second class citizens in the Islamic world.
Firstly, there are 57 Muslim states as well as 200-250 million Muslims living outside them as minorities, itās a mistake to talk about āthe Islamic worldā as if it were a monolithic block, it is not. But to the answer itās true that in some Muslim countries women have little rights, but a much stronger correlation can be found in the economic and political situation in those countries than in the religion of the countryās inhabitants.
May I ask who was the last Caliph? And why is it that there isnāt another?
The last official Caliph was Abdulmecid II. Itās a very long and complicated story but Iāll try to explain briefly what happened. The last Caliphs of Islam were the Sultans of the Ottoman Empire, which was the worldās last Islamic state. A previous ruler Abdulhamid II controversially dissolved the Ottoman Parliament in 1878 after a Russian invasion and unrest in the Balkans, and effectively made himself a dictator. This situation continued until 1908 when huge opposition to the Sultanās actions spearheaded by the secular nationalist Young Turk movement forced Abdulhamid to return most of his powers to the reinstated Parliament.
Later in 1913 the Committee of Union and Progress, an authoritarian vanguardist faction within the Young Turk Movement overthrew the government in a military coup, forced Abdulhamid to abdicate and instituted a single-party regime. The CUP then persecuted non-Turks in the Empire (most notably Armenians and Arabs) and disastrously took Turkey into the First World War on the side of the Germans, mainly because they wanted to conquer the Turkic regions of Central Asia from Russia and create a united Turkic nation state. The Arabs rebelled against Ottoman treatment and joined forces with the British and French in overthrowing Ottoman rule what later became independent Arab states, and the Ottoman Empire was soundly defeated and was occupied by European powers, and a new Sultan, Mehmed VI, was appointed, who surrendered much of the Ottoman Empireās lands to Britain, France and Greece.
An Ottoman resistance movement was founded to challenge this capitulation, lead by former CUP members like Mustafa Kemal, which by 1922 succeeded in forcing the European powers to remove themselves from what is now modern Turkey; though they failed to kick them out of what is now modern Iraq, hence why the todayās border between these two states is so illogical, itās simply an armistice line between the Ottoman resistance and the British occupiers. Mehmed VI was forced to flee the country in disgrace, and the Sultanate was abolished. The Turkish National Congress then elected a new Caliph (though not a Sultan), Abdülmecid II. He acted as Islamās Caliph until 1924, when he was forced to resign and expelled from Turkey by the ruling Peopleās Republic Party, which was in the process of eliminating its potential opponents as it went on to attempt to create a totalitarian atheistic ethnic-nationalist state in Turkey, and ruled the country until the first democractic elections in 1950 when it was overwhelmingly voted out.
Then what is a Jihad? and why is Mecca so important? What exactly does it represent?Also I heard that Islam has a holy week like in Christianity, so what exactly is the holy week about?
Jihad means āto struggleā or āto striveā, and in an Islamic context means to exert yourself for God, and in this sense has quite a broad meaning. In terms of Islamic jurisprudence,
Jihad refers to fighting against oppression, the greatest Jihad said to be speaking the truth before a tyrant and getting killed for it, this Jihad can include physical fighting.
We believe Mecca (along with Jerusalem) to be a place marked by God from the beginning of time to be centres for worship of Him. It is also the birthplace of Muhammad and where his mission of Prophethood began. There is holy month in Islam (Ramadan), but I donāt know of any āholy weekā.