I lost my invisalign. i'm not wearing any at the moment. my next appointment is wednesday. am i going to be fine ?

No worry: You should immediately go back to your previous aligner and have your dentist or orthodontist order a replacement for the lost one. Good luck.

Yes: the next set may be a bit tight, but you should be fine

No: Call your treating Dentist or (hopefully) Orthodontic Specialist so that they can order a new set of trays for you NOW. The longer you wait, the more relapse, the less the chance that you will have to step back and repeat some of the treatment you've already been through. Moving on to the next set of trays before you have completed movement with this set can throw treatment off completely.