A new breakup, a new love but old habits

I havent posted for a while and i thought i should start again. so I broke up with my boyfriend and I started self harming again. I stopped eating and cried a lot. One of my mates who I loved asked me out 3 weeks later. That was about a week ago. But I feel like I still have feelings for my ex which is hard because I really badly love my new bf. The stress and emotions are starting to take over me physically and mentally. During this week alone I have punched 2 students, threatened a teacher, punched the walls of the school, damaged school property and had 2 breakdowns, all this ever a period of 3 days,my boyfriend is there for me thank god but I still feel like something is missing. I’m becoming a danger to myself and those around me and becoming stuck. I see myself becoming more aggressive, upset and lost. My moods change every hour. But the only time I dont seem to be like this is when I have 30mins time with my bf at school (the only time I get with him during the week). He has helped me with my heartbreak and showed me that love can have good endings however my old habits are coming back…..this will destroy the new relationship I have developed and breakdown the new me that has began to form