He doesnt like me back; how do I get over him? :(?

im sorry i dont have much adive for you but i just went through something semi-similiar! a guy even told me he liked me so much he couldnt even put it into words and sent me hearts and flirted but then a few days later told me he didnt feel that way anymore and asked out my friend... (but he liked her previously) i have no idea what to do either :( just know ur not alone