Where does ani mamin say that he's coming tomorrow?
AFAIK that's a bunch of garbage.
My Ani Mamin says I believe...that Moshiach will come...and that he CAN come any day (be it today, tomorrow or 50 years).
Look in Igros Moshe O"C Chelek 5, Siman 8, where he explains the chiyuv letzapos lemoshiach, he writes
"דהחיוב בכל יום ויום לצפות כעין ודאי שיבא היום". Check out the whole Teshuvah.