My friends forgot my birthday

So today is my birthday and all my friends forgot. I had reminded them so many times that I thought I was getting annoying but honestly they didn't care. I got to school and they finally said happy birthday after I told them. They should've remembered. I felt so sad. This is exactly what happened last year. They didn't even try to make up for it. I have the exact same birthday as another girl and it hurt to see her friends showering her with gifts and making her feel special. I have a large group of friends of 12 but I really am close to 6 of them and for their birthdays I got them gifts and made them feel great. But no one even remembered mine. This one girl called Julie said she knew it was my birthday but because I got her a present 1 week later than her birthday (because I was poorly), that she is waiting till next week to give it to me so we can be even. I think that is so petty. Today was such a bad day and one of my closest friends came up to me and said "I'm so sorry we all forgot it was your birthday." I'm glad she apologised but she forgot my birthday last year AND the year before aswell. So I don't know whether to believe her. Even some teachers were asking me if I got anything from my friends and I had to say no. Usually people in my school have a big badge on the birthday and loads of bags of presents. I had nothing. Some people even laughed at the fact I didn't get anything. I want to cry but I know there's no point. I know I should be more grateful because my family made me feel great (although my dad isn't even around) but I still feel crap. I'm so nice to these people and they didn't care. This is the worst birthday ever and I just feel like isolating myself because of it. I don't even want friends anymore. I'm just adding everything up and I realised that they insult me at times and I dont notice it till now. Like pointing out my insecurities. Now that I'm realising this, I don't know if it's all a joke or I'm overthinking things. I dunno.