Hey Jordi, Yes, "I really messed up with..." is a good alternative. It is also common to hear "I screwed up...." (tal vez esto sea un poco mas fuerte) "To screw up" means to make a big mistake. (Esto significa cometer un gran error.)

I don't think that " I PUT MY FOOT IN IT" = "I PUT MY FOOT IN MY MOUTH". As far as I know they mean two completely different things. If you talk with Black Americans you might hear us say "I put my foot in it" to mean that I put my all in something or did something really well. Although Black slang and colloquialisms have become popularized, I'm not convinced that most others use this phrase (although, nonblack southerners probably probably do...) And little suggestion, it might be more natural to say: The I REALLY MESSED UP. I asked Laura if she was pregnant... instead of I MESSED UP WITH LAURA. I asked if she was pregnant... but really both are fine

Other ways to say "Put my foot in my mouth"; I had a faux pas today while speaking with Laura... I made an embarrassing mistake today while talking... I really messed up today while ..... I said the wrong thing today while speaking with....

Thanks, everyone!

Another very common saying is "I really made a fool of myself with Laura", or "I really embarrassed myself with Laura". It puts the emphasis slightly more on you and the fact you looked silly, rather than on how upset she is/was, but it's basically the same thing.