Is it depression ? Or unhealed wounds ?

So Ive been wondering for quite literally years if I have depression, or possibility seasonal depression. Tonight is one of those nights. Sometimes it seems anything can set me off, it takes a lot but once I break down I break down hard. I went through my diary just now that I’ve had since about 2012, and nearly all the days I recorded were bad days where I talked about feeling so alone, being jealous of “perfect families” and not wanting to suffer through my life anymore. I was definitely not dealt an easy life, as with everyone else I’m sure, but I’m just wondering where the line between “has a lot of pain and needs to get it out, plus can be hormonal sometimes” and “depression” lie. I literally don’t have anyone to talk to about this but I looked through my diary and literally for the past 6 years I’ve been writing the same things and feeling the same pains. Please, any help.