As bipolar person, I don't know about that.
One thing you could do is call a drug store or two, and ask what they think.
I go to the net when I want to learn about medicine, drugs.com said,
"The recommended starting dose of Lexapro is 10 mg once daily. If the dose is increased to 20 mg, this should occur after a minimum of one week."
"I'm on a very low dose of Lexapro (5 mg once every morning). When my alarm for my second medication went off today (about 9 hours after I took my Lexapro) I accidentally took the Lexapro instead.
"I'm just a little worried right now, I know it's lowdose but because of the timing should I not take it tomorrow and just wait and resume taking them normally on Monday?"
Putting that all together, what do you think?
Again, you might want to call a pharmacist or two.
And you could look up on the net search, and type in: Lexapro
and see what they say.
Let us know what you think.