What u suffering is obsession of going something wrong with ur near and dear ones.U also having free floating anxiety
If ur reapeted thoughts affecting most of ur routines and making it to perform a special kind of rituals,affecting ur study,and u feel that what u thinking is excess and if u r distressed about this then pls consult nearest psychiatrist
.U can visit urself if relative not coming along with u.
This happens because of some chemical (serotonin)changes in ur brain and so U r not able to control ur mind. unless this chemical doesnt get replaced u will not able to get relief or control of this.Now a days lot of advanced treatment available which will help u to improve ur concentration and decrease ur distress.
What u read in Secret book and interpreted it is just superficial and those thoughts r causing distress r not deep one in hierarchy of thoughts (so it is distressing,and those r not deep one doesnt get converted in reality)