Adjustment of Status - I-485

I've been wondering about what goes on with USCIS when it comes to processing of applications. According to them, they treat the cases as they are received which in other words means on "First Come First Served" basis.

Understandably, a case earlier received could be delayed due to RFEs and therefore makes cases that are later received to be treated before the earlier ones. Now what explanation could be given to my case with no RFEs whatsoever that has not been approved close to 100 days after filing and you see cases later than mine getting approved?.

I've raised 3 Service Requests so far. And the response to them are pretty generic. Below are the details of the SRs and their responses:

First SR raised by phone call on Jan 19, 2016
Assigned, Response Sent and Completed on Jan 20, 2016
Response: "Your case is currently under review. You should receive a decision or notice of other action shortly."
Response was sent to my email om Jan 20, 2016.

Second SR raised online on Jan 29, 2016
Assigned, Response Sent and Completed on Jan 30, 2016
Response: "Your case is currently under review. You should receive a decision or notice of other action shortly."
Response was sent by paper mail and I got it on Feb 3, 2016.

Third SR raised on the phone on Feb 2, 2016
Assigned, Response Sent and Completed on Feb 3, 2016
Response: "Your case is currently under review. You should receive a decision or notice of other action within 60 days from the day of this response."
Response was sent by paper mail and I got it on Feb 6, 2016.

I sent the applications (I-765, I-485, I-130) TO Chicago Lock Box on Oct 31st 2015 and my priority date is Nov 3rd, 2015. Biometrics completed on Nov, 30th 2015. My cases are still stuck at "Case was received" for I-130 and I-765 while I-485 is stuck at "Fingerprint Fee Received" till now.

I cannot seem to picture what could be causing the delay. It hurts so bad when you see people that applied even in December 2015 getting approved for EAD/AP and yours seems to be heading for nowhere.

I contacted the congressman representing my district and the response USCIS gave the caseworker was pretty generic as well. For how long will this continue?.

Please anybody in my situation in here, lets brainstorm on what other options are left for us to explore. I'm sick and tired of sitting at home. I've been applying to jobs but it seems most of the places I was called for interview are pretty far and are not serviced by public transportation. My wife who could have taken me to these interviews works like clock just to make sure we are surviving in the house. We cannot afford to miss an hour of her paytime.

I need the EAD to get my driver's license and without it I'm stuck at home. I really dont know what else to do.

Please, can anybody tell me what are the probable causes for the delay and what else can I do?

Thanks and sorry for the long write-up