I can’t stop crying

So...this is more of a way for me to vent and hopefully stop crying. I never really cry. It’s not that much of a rare occurrence but it just doesn’t commonly happen. Well, yesterday all I wanted to do was cry. I don’t know why. No idea, as soon as I got home from school, I had a 15 minute crying session then went to sleep for like an hour, woke up and cried, so on and so forth. For no particular reason. I just couldn’t stop crying. This morning, I was fine. Then it happened again. Crying. For I don’t know how long. I think today’s is partially because my parents are going away for a couple days and I am very attached to them. But I don’t even feel sad about that. I don’t know, they’ve gone away before but I have never cried so much and especially not in the first day. I just can’t stop crying right now. I have absolutely no idea why. Every little thing sets me off. I don’t know what to do to get over this and nothing seems to be helping. Any tips? Advice? Anything?