I have intrusive thoughts but they're not "this isn't reality" like yours. Whenever I get really upset, I'll yell a phrase over and over again in my head. Sometimes I even hold my breath so it has even more of an effect. It's along the lines of "stop it", "help me" and other dumb, sometimes nonsensical sentences. Doing this helps me calm down when I'm getting worked up and it's a huge release, and people never have to know I'm doing it!
About your thoughts though, you said you can't seem to get things "right" lately? Well this is probably a dumb idea but maybe you can find or make a small object that you can keep in your pocket and carry it around with you. That way, no matter how "off" you feel, you can take out your object and notice it hasn't changed, it's constant, it's familiar, and that may help you feel safe and secure again. If you've seen the movie "Inception", I'm basically talking about the "totems" they'd keep on them to remind themselves of reality. Hope I helped in some way!