I screw everything up

I'm a weirdo. I am kinda shy and is not good at making friends. If I meet someone for the first time I'm awkward and weird and I talk about dumb stuff or hardly talk at all. I met this guy online and we've talked for months. Everything was perfect. I felt he really got me and understood me. I'm not really like most of the other girls of this generation (I'm not trying to generalise or anothing) I hardly post on social media..and he didn't care. I was completely myself and I thought that he liked me the way I was..and I was so happy i could say anything to him..even if it was stupid or if my jokes weren't funny he wouldn't care and he'd still make me feel so good about myself and make me feel like a princess. Then we met in person and yes even though I was comfortable with him i was a weirdo. I don't even remember all the dumb things i said coz it was a few months back but I know I couldn't even keep eye contact. I just screw everything up. After that day things were so different. He spoke to me differently..stopped saying goodnight and somedays he wouldn't message at all. When I ask what's wrong he says nothing..or he's busy with his new job or whatever but he's always on social media so he can't be so busy that he can't even send me a message. When I say that I miss how things were before...he says he's the same. Surely he's change in behaviour means something right. I know the key to everything is communication but what do I do if when I try to communicate he just blows it off and pretends like nothing is wrong. I am so confused and I'm sure it's all because I was weird that day we met. It just breaks my heart coz I know that it takes a while for me to be myself with someone and wish he wouldn't give up on me so easily without giving me a chance.