Ssi question

So I moved the end of June to a different state and changed everything I needed to with social security. Well a few weeks ago I checked my online account as I do every couple weeks. I noticed I got a couple hundred dollars increase. Well I checked my account again tonight an noticed that one of my checks is completely gone. I am on ssi and I got a different check because one of my parents are on disability. I was told years ago the only way I could lose that check was if I got married. I’ve never been married before an it came as a complete shock that It was gone. Has anyone had this happen? What could of caused me to lose that? I’m starting to stress myself out over this.