How can I overcome the whispers of Satan that prevent me from worshipping God as I should?

The cure for what you are suffering lies in sincere repentance to Allah, occupying yourself with reading and contemplating the Qur'an, and increasing your supplications for forgiveness (Istighfar), remembrance (Dhikr), and prayer (Du'a) so that your heart may find tranquility. Allah, the Exalted, says: "And We send down from the Qur'an that which is a healing and a mercy to those who believe," (17:82) and He says: "Unquestionably, by the remembrance of Allah hearts are assured." (13:28) You should also attend congregational prayers for all salaat, increase your voluntary prayers (nawafil), associate with people of piety and righteousness, and beware of accompanying people of transgression. Learning religious knowledge (Shar'i knowledge) instills awe of Allah and foils the devil's plot. Allah, the Exalted, says: "Only those fear Allah, from among His servants, who have knowledge," (35:28) and He says: "Indeed, the plot of Satan has ever been weak." (4:76) For the strength of faith protects a person from the devil's domination.