How to get over an ex boyfriend

I am struggling getting over an ex, i really looked upto him and hes been seeing other people he has genuinley no love for me but i still love him immensley. Can someone tell me what to do. I am struggling and have panic attacks thinking he might never miss me.. i know its wrong to be jelous i love him very much and didnt see this coming. Hes turned into a heartless player and i never thought he would be like this xxx