Here’s the deal.... I need serious advice asap!

I’m 17 and I have great Issues with expressing what I feel when I fall in love. If I’m honest and extremely afraid of saying what I actually feel when I know the situation is 100% uncertain.... I’ve been seeing this amazing guy for the past 4 months ad we are friends with benefits. I must say he was my first time and he’s the only guy I’ve ever done it with, so yeah.... also our “thing” is exclusive (which means we don’t talk or do things with anyone else). We go out for dinner, he’s met my parents and I’ve met his, we go to the movies and basically do almost everything together. It’s important to say he’s invited me already to one of his best friend’s bday and I felt so happy there... I felt welcomed and exited! He’s 19. So here’s the deal, for the past month I’ve been acting weird because I accepted the fact that I fell for him.... which keeps me with a huge knot on my throat with the constant need to cry it out because I’ve been wanting to say what I feel but fear blocks me completely, leaving me with swallowed feelings that start making me feel shitty. I trust this guy completely and I care for him a lot... I know for a fact that he likes me and cares for me because I’ve been through a lot of shit for the past month and he’s always been that unconditional supporting hand and crying shoulder. I’m afraid to say what I feel.... but I also feel tired of feeling so shitty because I’ve been keeping what I feel for so long. I truly need help because I need to stop being scared!! I just don’t know how.... I’m afraid to fuck up. I know people say “If it’s not meant to be” or “If it didn’t happen maybe it’s for the best” or whatever... have you ever just felt one has become so important to you.... that you’re just scared shitless to fuck up of lose that one person? Well, that’s what’s happening to me. And I know I probably shouldn’t let fear overpower me but I tend to close myself inside my own mind when fear hits me....

I need advice asap!!😪🤦🏼‍♀️