I hope you eventually become accustomed to giving them the Invisible Man treatment for their callousness. A voice is powerful yet they take it away from you. Try surrounding yourself around people who don't disregard you like your parents.

My mom is a big and long talker. When I was a teenager I realized that when having a conversation with Mom that I had to interrupt her from time to time in the conversation otherwise I wasn’t going to get a chance to talk. But surprisingly to me Mom didn’t seem to mind as long as I didn’t do it rudely or over and over. Normal human conversation sometimes requires a person with something useful to say to interrupt from time to time. While it’s not rule book etiquette, it’s actually a useful life skill - To be able to judge when you can and should interrupt to express something useful to the conversation. That doesn’t mean doing it often or rudely but quickly sliding into a pause with the point or idea you wanted to make. Just turn it around on your parents and occasionally interrupt during a conversation - But not rudely, not unreasonably. It could well be that your parents are from the same school of conversation as my mom…

You should seen what I had for dinner last night. It was a really nice steak, grilled, and a sweet potato. It was very good! Yeah, it was a good day!

My whole family does this to me. It's like I don't exist except when they want something from me.