Not over him

Started talking to my ex over the summer again and thought we were going to get back together but he told me he is seeing someone else . It’s been 2 weeks and I’m not like myself I can’t eat or sleep well! I know I deserve better than him but him rejecting me hurts a lot! I stalked them for a while and finally decided to block all of our common friends and him! Gonna be 25 in a few months and I’m freaking out I won’t have a steady relationship before I’m 30