How can you tell that it’s opened? Can any other plus size people help me please?

I feel so dumb, but how do I know the disc has opened when I insert it and that it’s not still folded up? Of course I tried feeling but I don’t even know what I’m supposed to be feeling for. I can’t tell if it’s opened or not. I’m so frustrated and want to cry. I’m supposed to go on a cruise next month and of course will have my period. I feel like this will ruin my whole cruise now because I can’t get this figured out. I used to use a cup, but since gaining weight it doesn’t seem to work anymore and always leaks. Trying a disc now and it’s so frustrating. Seems to leak no matter what. It’s making me hate myself because I feel like my body is the problem since a cup used to work fine.