How can i make this better, after i told her this lie?

i've been with my girlfriend for 3 months, me and her had a little argument, and when we were i told her about a lie that i told, now she won't let it go, this happened on saturday night, she keeps saying how much she loves me and that she don't want to break up but if she still feels like this then she don't know.., i've been going threw a deep depression for about 4-5 years, i've just started to get a litle better, now i'm right back to were i started with this, i told her about how i feel, and trust me it's very bad, but all she says is, yea i know, but you don't know how i feel, and i ask what, and she says i don't know, i mean here a am falling apart, i was already near the brink to begin with, now i pretty much reached the end, but just because shes a hurt and mad, she ain't there for me, she dosen't even care i think, and this whole time i thought she was a sweet innocent girl, i seen that everyone sees that, and the sick thing is, i don't want to leave her, i love her, even if this is killing me, i won't leave her, besides i lied when we first met, i said how i drank allot and did some bad stuff, but i said that cuz i'm depressed with no self confidence and insecure, so i said it so she would think i'm a wuss and so i wouldn't run away scared, i just wanted to feel like i did something for once in my life, but i'm beating this depression and i don't lie no more and now that i'm used to her i don't lie, besides i only did once