Can using too much mi paste on teeth be bad, i am afraid i over did it, and rinsed with act in the evening before bedtime. would this damage my teeth?

Mi paste is mild: Try not to swallow too much and typically only a problem if you are allergic to milk/dairy. It comes in two forms - with or without fluoride, if using it often use the non-fluoride form so that you do not ingest too much Fluoride (considering you are already using act and probably a Fluoride toothpaste).

No - you will be fin: Just use the manufacturers instructions which is a pea sized amount henceforth and you should be fine. Also obviously use and spit out - don't swallow. Hope this helps.