I cannot sleep and I feel fear and obsessive thoughts.

The Prophet, peace and blessings be upon him, instituted etiquettes for sleep that remove obsession (waswas) and fear, as they repel Satan and his whisperings. Among these are: reciting Ayat al-Kursiy, for whoever recites it, Satan will not come near him; joining the palms, reciting Al-Ikhlas and the two Mu'awwidhatayn (Al-Falaq and An-Nas), blowing into them, and wiping over the body with them three times; and reciting the last verses of Surat al-Baqarah, for indeed they suffice against all evil. Moreover, reciting the Qur'an and consistently performing dhikr (remembrance of Allah) in general are means of repelling obsession and fear. It is also advised not to indulge in obsession, but to try to cut it off and seek refuge from Satan.