No problem I lost three people when I was 15 in a matter of months as well, and know that it can be hard.
Thank you. I am going to take all of that on board
You are real young to have to deal with so much grief. Try getting out your emotions in a journal or in some way that you feel comfortable. Write your loved ones, if you don't feel like you got closure. This way you can tell them how much you cared and get to say goodbye in a way that brings closure for you. The main thing to remember is that the pain will go away.
To get back to your old self you need to try to go out with those same group of friends and slowly I believe you will open back up. Talk to your parents and your boyfriend about your grief as well. Just knowing that you have supportive family and friends will help you as well.
The most important advice I can give you is don't let this be your defining moment. Don't let these four deaths consume who you are. It's ok to grieve, but its bot ok for the grief to take over your life. The loved ones that have passed on want to see you strong and living a happy life. They want to see you succeed and not let their deaths take over your life. The hurt and emotions will take time to get pass but you will be fine just as long as you let those emotions out, and remember to find joy in your life.
If you need to talk message me I am here to hear you out.