Insecure

I’m 16 and I have a boyfriend we’ve been together for over a year, I have a good life, but I’m so insecure, I just feel so empty and alone, and I hate going to the gym or swimming pools, being in a bikini, I just really don’t know how to start loving myself and feeling happy about myself and my body, however when I’m with my boyfriend it’s like it just disappears, he makes me feel so great about myself and I forget about all my problems , but I just want to maintain that feeling but I can’t !!?? Any help :(