Can somebody explain to me why the thoughts of the male semens?

can somebody explain it to me why the thoughts of ingest the male semes make me feel vomit like symptoms even seeing the while fluids of it make me feel sick. yuck. how i can get over this? do u think its connected to at time 15 yrs. ago when a male make me suck his peter and he let his fluids go in my mouth?? it was unwanted is this connected. thank you very much.