I am student who did very well in the past, but now I cannot concentrate. I am feeling bad in college. Tell me some supplications. I want to study. Help me.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger. 

We ask Allah to open your heart for the good, to make your matters easy, to help you in your studies and in His obedience, and to grant you purity in your intention. Know also that when a Muslim intends to serve the religion through studies he will be highly rewarded in his studies and this becomes an act of worship.

Moreover, we advise you to do the following:

a) Recite as much Quran as you can while considering its meanings. Allah Says: {And We send down from the Quran that which is a healing and a mercy to those who believe (in Islâmic Monotheism and act on it), …} [Quran 17: 82].

b) Keep away from all major and minor sins. Sins have very bad effects on the life of the Muslim, such as eradication of the bounty of Allah, lost of livelihood, increase of worries and forgetfulness of knowledge. Ibn Mas'ud said: ‘I believe that a person forgets knowledge that he has already gained due to a sin he committed’.

c) Manage your time, use every second of your life and avoid wasting your time in useless matters.

d) Keep using Ruqyah al-Shari'ah and the supplications.

e) Frequently make Dua. Allah Says: {And your Lord said: "Invoke Me, [i.e. believe in My Oneness (Islamic Monotheism)] (and ask Me for anything) I will respond to your (invocation). …} [Quran 40: 60].

On the other hand, we do not know any specific Du'a pertaining to studies.

However, you may ask Allah with any words to indicate that purpose. For example you may say: 'O Allah! Help me in my studies, and the like'. You should ask the good in this world and Hereafter as well.

Allah knows best.