Help??

Since the beginning of December I've been really depressed, initially it started because my boyfriend wasn't treating me in a particularly nice way but mid January we broke up and since then my depression has gotten much worse. It's been a month and I thought I was starting to get better but I've got this wave of sadness again. A few weeks ago I started having suicidal thoughts but I never intended to go through with them, I don't really understand what's happening it's like I want to kill myself and be done with all the pain and sadness but I don't want to die. I don't really know what to do I went to the GP and she literally laughed me out of her room and I can't tell my parents because it would hurt them a lot to know this