What the hell should I do? Does she really love me?

I advise you to let go. There is no need to keep you in pain. Long-term pain is better than short-term pain, hard-hearted, break up. Although it is difficult, after all, there are feelings. If you don't want to, then compete fairly, grab and gamble with that person, whose feelings are deeper, and if your girlfriend chooses someone else, there is nothing to say. I can see from your words that you are a very responsible person, but not everyone in this world is so responsible, what's more, the shelf life of feelings is not long.