Scared of getting hurt again

So like I just started high school like a week or two ago. I wanted high school to be a fresh new start for me because middle school was pretty hard for me. I've had a lot of fake friends who tried to use me and people who stabbed me in the back and made me feel so insecure and lonely. I thought high school would be a bit easier but it actually seems harder. It's so hard to make friends and I'm kind of a shy person so it's hard to be outgoing. I'm trying to change that and try to put myself out there but it's really hard especially in a new school with new people. I'm not that shy once you really get to know me. However I really have trust issues cause of all the people that hurt me. I feel like no one really cares and appreciates me as much as I do and that I'm always the one that cares more. I want to find real friends but I'm scared that what if they soon leave me, like you never know who's going to leave you and it's like the more you trust people and let them into your life they take advantage and find a way to leave you.Also there was like this guy who I've loved for 3 years and I believe he's my first love. Like I never really loved anyone as much I loved him. We were good friends and pretty close at a time but soon we started to fade. He dated someone else who really changed him but soon left him and broke his heart. I've tried to tell him how I felt but I don't think he felt the same way or maybe he did but he soon lost interest. He really broke my heart and I just feel like no one will really love me for who I am, I'm not even that pretty. But like there was is guy in one of my classes who really seems smart,outgoing, and funny. He really made laugh on the first day and made my day a bit better since I had a horrible day. However I'm not sure if I'm starting to develop feelings for him. I guess I'm trying to deny it cause I'm scared to fall for someone else like he seems so cool and all while I'm a stupid shy girl. Like I do wanna get to know him better and be his friend first but I'm scared of getting attached and being heartbroken again. Like in high school everything is so different and more stressful like they give us so much homework since day 1 and like I want to be more serious about my studies but like I'm so stressed out and there's so much in my mind.