I'm sorry that your week has been such a downer. I take my shot on Sunday evening, so Monday is a real down day for me. I spend all that day on the couch, not wanting to move. By Tuesday, I'm a bit better, and by Wednesday I feel great and full of energy, but I'm still in pain, especially my knees. This week, I felt great on Wednesday and went shopping most of the day. Then yesterday, I went out to lunch with friends, cooked and baked in the afternoon and then went to a meeting in the evening. By the time I dragged myself home at 10:30 last night I was in so much pain, I kept falling in the floor, and couldn't sleep last night. I'm spending the day on the couch today.
Taking MTX seemed to be quite a shock on my system, physically and emotionally, but the more I've taken it, the more I've gotten used to it. Maybe you can give it a try for a while and see how your body responds once it gets used to it. If you continue to feel more and more down all week, then talk to your doc.