Dastardly,
for what my opinion is worth, I would go with PVC's advice. Start with a conservative target weight for your intensity day, and work back to 90% of that for your 5x5. In numbers, aim to squat 100Kg x5 on Intensity day, and do 5x5 of 90Kg on your volume day. Possibly lower, as you burnt yourself during the first week.
Let your body adjust to the new rythm, I'm sure you will see the difference. You've got plenty of time to increase your weights.
I also see no problems with your switching to TM; if you felt you could not continue on linear progression, it's a sensible decision to switch. Yes, TM will make your progress slower, but I can't see that being a huge concern, especially if you plan to make strength training a long-term activity.
IPB