I'm sorry that happened to you. With your mother dying, and the 24th always being a hard day for you.
And then he kinda weazeled his way in, as men are cursed by evolution to endlessly and insatiably desire to have sex. Some are nicer than others. Some truly and genuinely do fall in love with you. Others are cunning and more focused on satisfying themselves.
Sometimes it's nobody's fault, as there's a third option: It might be the fault of the design of the system-as-a-whole. It's possible for a system with no broken parts to still give an unfavorable response, simply because the overall design of the system, how the parts interact with one another, and circumstances which are beyond anyone's control, all combine to produce a less than favorable outcome, and there are no defective people, just a less than ideal environment we live in.
So it's not neccessarily your 'fault', as that would imply you are somehow defective, and that's not the case. And it's not necessarily his 'fault', as he's just a man doing what men are programmed to do by evolution. It could be evolution's fault for making us all this way.
It is a bit insensitive of this guy to afterwards say he was just lying about liking you and then stop speaking to you. That's a jerk thing to do. (Some men are jerks.)
The first time usually isn't the greatest thing in the world. I do hope there are better times waiting for you in your future. You deserve better, with someone who will listen to you, someone who wants to hear about your mom, and do other things with you besides sex.
Have you been to Hospice yet? They have free counseling for people grieving over the loss of a loved one. It sounds like this is still very hard on you. Having someone you can talk to about it can often be cathartic. Sometimes a small support group with other people who have similarly lost someone special, so you feel you're not the only one who's had this happen. Or a pastor of a church is often good at listening to your story, as they understand that it's the listening that is helpful, and they chose to be a pastor because they genuinely care about other people and they want to help other people become whole.
I won't pass judgement on whether it was rape or not. That involves semantics which can get bogged down into an endless debate on trivial nuances, since everyone's personal definition of rape is different. You can label it 'rape' if that helps allieviate the blame you may feel, though you're not to blame anyway because the blame lies in the design of the overall system and circumstances itself.
Best wishes. I do hope you can find a counselor / therapist / LMFT / pastor / peer, who can help you deal with all these feelings you are having. It's called 'processing', as in one needs to process their feelings and have their feelings validated by someone, and that somehow makes it OK to have those feelings, and then you feel OK again. (I really don't understand why this works, I just know from experience that it often does. The brain won't let go of the hurt until you tell your story to enough people who know how to listen, and they validate your feelings, and that somehow satisfies the brain, which can then let go of the hurt.)