Purity and ghusl

Sorry to bother you but i forgot some questions I try to amend them on the last one but it couldn't work 1. I feel like my impurities and semen make the whole house impure like if i miss one spot and somone comes in bathroom after me they whole namaz and fasts are incomplete and thats cuz of me and im giving them the sin. 2. I have doubts that i did not do ghusl properly i remove the impurities i make intention by saying i want to remove any impurities on my body so that i can pray and fast and that im purified and in state of ghusl. Then i wash up to my elbows 3 times Then gargle my mouth with water 3 times Then i shower my head and neck with water flowing over it and wash my right shoulder 3 times then repeat with left . Is this the right way. I feel like when i drop an impurity or someone touches me it breaks their ghusl