Friends being problems

Sorry guys I just need some advice. Sorry for the rant but I just realized I have some pretty toxic friends that are nice to me one moment and a very rude to me more often then not. I am a really easy person to just walk all over. And pretty gullible to so sometimes they find it funny to be like oh there was a test today and leave me freaking out and then feeling stupid. I am in high school in my teens 16 though all my year group is mostly 17. Some of these friends in my group lie to me and using me more often then not making me feel negative. Like tonight I was at a firework show with this group of friends talking to a different friend in the group and one of the girls one yelled at me to move so she could talk to this friend I was talking to. Then later she was barking at me on the phone asking where her wallet was. When I said she left it in our other friends bag who was with me she said to walk over to her house and take it to her. When i did she grabbed it off of me turn to my other friend and thanked her really nicely. I been called stupid and an idiot when I asked for an explanation on something that I didn’t understand. Been left out of many events and groupings. Which left me feeling like shit. I thought they where just joking for some of those things but now thinking about it I am feeling worse about myself after hanging out with them. Some of them are childhood friends so don’t want to cut them out of my life. But one day their nice to me the next day their super rude. I am not a great person at confronting someone and when I did individually, the childhood friend was like what, I am not mad at you don’t worry. When I try to tell myself their always like this it’s toxic, the next day their nice. It messes with my mind. I don’t know what to do. But I am really tired about feeling negative about myself and feeling like I am not worth much. I try to tell myself I will make new friends but then feel lonely. Sorry again for the rant. Any tips will be greatly appreciated. What should I do?