anxiety

So my boyfriend and I have been together for four months, but I'm afraid it won't be for much longer. I do have anxiety, along with depression, and when I get to overthinking, I can't stop whatsoever until I cry enough to fall asleep. However, the current deal is that I keep asking him if he wants to still be together because of these thoughts and he gets irritated because he keeps answering yes over and over again. I keep telling him that it's just something I struggle with-that I would still ask him even if we were married. He just doesn't understand that and it's making me miserable every single time he gets mad at me for asking that. What do you think I should do??