Alone but not alone?

I’m not sure how to start this without feeling I’m just complaining. I feel like my friends don’t want to be around me because I confronted them and I told them that they would have to invite me over to see instead of me just inviting myself because I feel like I’m intruding and bothering them and there response was along the lines of “oh well we won’t invite you because we don’t think to sorry if that hurts your feelings but that’s the truth”. It made me really sad and feel so alone especially since nobody did anything for my birthday my parents are in their 60 and my mom recently had surgery and my dad has been having problems with his knees so I understand why they didn’t do anything for me plus they believe after a certain age you shouldn’t be celebrated ( which is not how my older sister was treated at my age) but that’s besides the point. But my twin sister her boyfriends parents and boyfriend threw her a party and bought her so many gifts that when I saw her after she had to brag and she me all of her presents and tell me how much fun she had and I listened until she finished and then I started to cry because I felt so forgotten and unwanted, but then she got upset because I couldn’t put my feelings into words ( I struggle to do that because I never figured out how to interpret them) so I just shut down and stopped cry because she got mad. I know I have family and “friends” but I feel like I have to mask so often but when I’m alone I just collapse almost I feel heavy and so overwhelmed and so much I don’t know how to process are handle.