seasonal depression & relationships

in 8th grade (i’m a junior now) i was diagnosed with SAD and they said i could do meds or get a heat lamp for light therapy, etc. my mom talked me out of meds so i don’t have those or a heat lamp but i’m seeing a therapist and have been since 8th grade. freshman year they said i had clinical depression (freshman year was awful and i was suicidal and felt hopeless for most of the year) and i’m still not on meds. it really sucks cause i’m depressed year round but during the late fall/winter it just gets so much worse and there’s literally nothing i can do about it and it’s ruined multiple relationships. i’m dating this guy rn who i’ve liked since my freshman year we’ve been dating since may 2018 and it’s been great but since i’ve gotten depressed again (winter) it’s just been a mess cause my mind thinks i’m not in love with him even though i know it’s just the depression rearing it’s head. i really want to stay with him and i’m just trying to get through the winter and see where i am. but in october i started having slight feelings for my best friend and i figured i was just infatuated and tried to forget about it, but it’s january now and the feelings are still there. i don’t know if i would date him or not but it’s just a weird situation because i know i love my bf but i feel like i love my best friend too. i would never cheat on my boyfriend and he knows that. i told myself that i’m just going to chill for the winter and if i still like my best friend by summer i’ll work from there. i don’t know if i came here for advice or what but i just needed to say that cause it’s about the two people who i usually go to. please don’t start calling me a terrible person or whatever i didn’t cheat and i never would but i already feel like a bad person and just feel bad overall so if you have anything bad to say please just don’t. but if you have anything that might help i’ll take it. i just feel so lost and i don’t want to anymore. and if you have any experience with SAD and have advice please let me know