Tilting in Chess

I feel like many of times I'm outplaying my opponent, the only problem is that I blunder 24/7 in blitz – unfortunately, I don't really have too much time to play rapid, so its hard for me to practice this way. I also use ChessTempo and have a tactics rating of ~1400. The problem is that I will literally sometimes lose 10 games in a row, and its due to dumb blunders like not realizing that a knight is attacking my queen. I'm also taking breaks, but that doesn't seem to be stopping my losing/blunder streaks. I know this is a vague question, but how do I get rid of my tunnel vision (it happens even when I double check moves)?

Or even better is there a relatively dumbed-down opening that makes it harder to blunder? 😂