You have correctly answered your question. But the given example is very confusing. 我（太）讨厌单相思 单相 思 单 and 相 can not be used together, 单 means one way, 相 means mutual. 我（太）讨厌单思 or 我（太）讨厌相思

yes you can say that ~in chinese 讨厌 is just like " hate or don't like "in english

Yes,讨厌 means "hate" 讨厌做某事 = hate doing/to do something fox example,我讨厌听音乐 = I hate to listen music

我（很）讨厌单相思= 我不喜欢单相思的感觉。 我讨厌（为这事伤心）掉眼泪。

yes,u can also use 厌恶 to show your sick of something so much