and they sayed as well, they will mail me the package. this was last thursday. but havent got anything up to now. and tomorrow i should go to the medical. once i wrote the embassy, they told me, not to do the medical before they contact me. so will it matter, this few days? can they bring problems after? or should i better cancel the medical tomorrow and make a new date?
thanks for ur help!

Not sure about where you are but here you need the case number from packet 3 to have the medical.

One of the dangers of getting the medical too early is that it is only good for 1 year. If it expires before your AOS, you have to do it over again.