I have this strong feeling that im worshipping other than allah (shirk)

Assalaam Alykum..in my past I never prayed I rarely read the Quran..but one day I started praying all 5 prayers on time.. I felt close to Allah to the point where I felt like I'm worshipping someone named Allah but isn't the true one...if I'm commiting shirk I want to repent but I don't know how because 1) the one I think I'm worshipping other than Allah is also named Allah so I don't know how to deal with this and how to tell the difference...2) I get a weird feeling when some one does dhikr or when I hear the Quran because something is telling me that "he's only your Lord how do they know about this" and " you are a kafir ..look at these Muslims there actually true Muslims not like you doing shirk" 3) I'm scared to do dhikr because I feel like I worship other than Allah.. I want to repent but I don't know how...please help..