My grandmother is one of my favorite people in the whole world. I love her with every bit of my heart. And she has been through some things that I can't even imagine, and others that are all too familiar. But her reaction to my experiences has always essentially been "I'm so sorry these things have happened, but buck up, it could have been worse." She doesn't mean "I've been through worse" because I know she applies the same line of thinking to her own experiences. This is her coping mechanism. Right or wrong.
And I know that I have used the same one throughout my life. I never thought anything was that bad, even just godawful stuff, I survived, right? It wasn't that bad. Coulda been worse.
My point is- to maybe give this a different perspective- that they may, in their misguided way, be trying to help you. This may be the way that they cope with things in their own lives. They may be frightened for you and they are trying to tell you how they imagine they would deal with it. When somebody we care about is hurt it can be really scary (yes, I know, it's far more scary for you than for them) and we don't want to mess things up or make them worse for them and I think that sometimes that's where this type of response comes from. They think they're lending you strength.
It may be useful for you to tell them flat out that they are not being helpful that they are dismissing you and that you are feeling unloved and kicked while you're down (if you're anything like me, confronting them about this will seem like an impossible task, I understand that, try it anyway.)