Adjustment of Status - I-485

on Sep 6 2016 i submitted my I-130 and I-485 based on family case ( married to US citizen) , October 9 i did my finger print, on Oct 15 they scheduled my interview on Nov 15 2016 , during the interview everything went perfectly and the agent approved the case an gave us the white paper and told us i will receive my greencard in 2 to 4 weeks , we left the building the agent called after 15 min to say that she cant approve us today because my case is still missing some files and check back with them in 90 days. a week after the I-130 status changed to approved but the I-485 is still showing "Interview Is Scheduled" , after 90 days i called uscis and they the case is pending because they haven't received my security clearance.
please advice me what to do ? is this normal ? any one facing the same issue ?

just to mention i have visited the US many times so i was fingerprinted many times at embassy and border check