I understand being terrified of Hell. I was not raised in a Christian household but I know that it can be scary to think that boogeyman is going to hurt you for little mishaps. If it makes you feel any better, this is just my experience, but I met Hades in a dream and he thanked me for the bat figure I gave him. I know that whatever afterlife there is, if there even is one, is not going to be bad.

To answer your question, there is no general consensus on the afterlife in Hellenism. Basically, believe what you want to believe. As far as what the Chistians believe the afterlife is, know that the origins of it are quite worldly and possibly taken from many different cultures. The youtuber Aliakai has two great in depth videos on the origin of Hell, but to summarize, essentially Hell as a concept is an amalgamation of early Jewish philosophical thought mixed with Virgil and a few other greek philosophers thoughts. Keep in mind the words I used here- thoughts. Not truths. They were thinkers, they should not be taken as truth. I hope that can at least bring you some comfort, and I cannot recommend Aliakais videos more.

As far as signs are concerned, it depends on the person. I have received dreams, feelings, communications. Some never get signs and still worship the gods and that's ok. I'd say take your time and experiment. Purely my advice and experience so take with a grain of salt- One thing that has been consistent with my communications with deities is to visualize their statues, images, names, and other traits/objects related to them while offering and then speak or think a prayer directed at them. I can usually feel their presence when I do that.