Could somebody please help me?

Well firstly you are not alone..they are just as anxious and perhaps more than you are. Just savor the moment of long time no see, smile brightly from your heart then as you approach and likewise are approached be sure greetings are amiable and do lots of hugging that will break the ice, then just be yourself. Definitely will be different than the last time you saw each other, your ex too, so just make the most out of the occasion and let bygones be bygones. Try to be as cheerful as you can be and the erflies in your stomach and the anxiousness in your mind will turn into erflies of glee and the anxiety will disappear. Bring with you small tokens of affection to give and to share, that is always comforting for everybody especially when they smile. Mostly just smile, smiles are very contagious and think happy thoughts..it will be just fine :)