Yeah, you overcooked yourself. This is entirely normal and expected. I don't start intervals until about February. Winter is for LSD and weight training. Cut way back on both volume and intensity. Make one or two rides pure Z1 on the trainer, 45'. Outdoors, 45' again, not over Z2 or probably about 125HR for you. Do that for a week, then test yourself with a harder ride. If it's still not normal, do the easy rides for another week. You should be able to easily reach your previous trainer HRs on the road. If you can't, you're still cooked. OTOH, you don't want to take time completely off or you'll lose fitness. Training at the edge is always a little tricky.
You can easily assess your training state by taking your morning resting and standing-resting HRs. Graph them in a SS or use an computer or online training log. Start now.
How to check for overtraining:
http://www.pponline.co.uk/encyc/0410.htm