Hey, I think you're being really hard on yourself. Yes, in any circumstance it's possible to think of someone who has it worse but that doesn't mean that what happened to you was OK or that you don't deserve to be supported. Whether or not there was consent in the past, if you didn't consent this time it was rape. I'm sorry that your mum was so dismissive and unhelpful. Is there anyone else in your life who you can talk to about this?
Did you have any professional help at the time of what happened? Either way, it could be worth trying to see someone about this if you can.