Help😔

Can you miss someone and not be sad? I saw something online that said if you don’t miss your SO when they are gone you don’t really love them, every since I saw that I’ve been freaking out.. me and my boy have been dating over 5 years now and ever since we started dating pretty much I would get really sad when we’d say bye. We only see eachother every 2 weeks bc he lives about 50 minutes away, and we’re both 19 as an FYI, so I’m not a 12 yo, haha, It was like I was depressed the day after we would hang out bc as soon as I’d open my eyes that next morning I would start to cry bc I knew I wouldn’t see him, I wouldn’t eat, or want to talk or see to anyone other than him.. and now I don’t get really sad or depressed when he leaves I feel almost normal, i feel pathetic but this is giving me so much anxiety it’s all I can think about, when I think about leaving I wan to cu idk what to do. Are relationships suppose to change? Im freaking out😔 he’s my bestfriend and makes me so happy I love him so much but ugh. Before this I would give anything to have that pain taken away but now if give anything to get them back.. the thought of not loving him anymore literally kills me inside 😢