Yes my friend some people tend to build resistance to antidepressants over time.
in 18 years I have built resistance to 20 different antidepressants.
BTW Seroquel is not an antidepressant. You can still build resistance to Seroquel, but it is not an antidepressant.
I have found a way to trick this build up of resistance by adding an SSRI with an SNRI and then throwing in a dash of Lithium and Lamictal with a splash of Xanax.
I have also found that switching off of the SSRI's and SNRI's and going with a Tri-cyclic can help too.
At this point if you have become medication resistant then it will be important for you to work with your Psychiatrist with the use of several different combinations of meds to get you adjusted.
I used to be a one trick pony. Just one antidepressant did the trick. That was many years ago. Now I must be a master mixologist to find the right combination of meds that will produce a response for me.
In the end if all else failes there is always the MAOI's like parnate or nardil. They work well but are very risky.
That sounds like a lot of added stress. I have had similar issues.
Depending on how long you have taken different medications, they can change effectivness. Please try to hold it together unitl you talk with your doctor.