I need help!!pest problem?

so i have a cockroach problem. They are the water-bugs. First i thought my room was messy so i cleaned every inch of my room. In total i have killed 7 cockroaches this week. i think that is enough i haven't slept this who week because i am scared of them. they fly and i find that disgusting. today i went with my dad to buy combat gel to kill them but i am scared it wont work, i don't know where they are coming from and i am tired. i am a 14 year old girl and am terrified of them. Can someone please tell me a way to kill them and make them go away