Not being a pharmacist, I don't know if Effexor and Trazadone lose their efficacy over time. But what jumps out at me regarding your post is that your anxiety/panic seem to be escalating into the realm agoraphobia. Something has changed and you need to figure out what that is. You also need to figure out what caused the anxiety in the first place. But, one thing at a time.
I am very pleased to learn that you will be seeing a new therapist this week. He/she will have the answers you seek and they are the only ones qualified to speak to your questions regarding medication.
That this runs in your family is very common. But this is another issue you will deal with in therapy, along with your fathers alcoholism. Like all the bones and muscles in our bodies, it's ALL connected. Works the same with our minds.
And you're doing everything right by seeking help.
Keep us posted about your journey and know that we are always here for you.