The fast is broken as soon as the menses starts. So, you need to make up for the days you miss after Ramadhan.  There is nothing to feel sad about it. The Prophet (peace be upon him) said, "Mentruation is that which Allah decreed on the daughters of Adam." Allah, however, relieves them of the rigors of the acts of worship such as prayer and fast, in order for them to relax and recuperate during this condition, which takes a toll on a woman's physical and emotional health.

Having said this, I should also point out that you may freely listen to the Qur'an, make dhikr and undertake whatever righteous deeds you can afford to in this condition; they would compensate for wahat you may otherwise miss, due to menses.