Bad week for an injury!

Of all weeks to have an injury I have one the week of Thanksgiving!! Hip Flexor injury from I don't know what...I think I was doing something relatively normal and tweaked it. Tried swimming Tuesday and did but used the pull buoy bc kicking hurt. It got worse on Wednesday when it hurt to walk and to lift my leg just to get in the car. So, needless to say, I have done a bunch of nothing on one of the most calorie filled weeks! BLAH! I'm itching to get back out on the road or pool! I have a marathon in January and IM in May. I guess sometimes our bodies just need a break. Any advice on getting back on to the training plan?Take it easy the first few workouts out??? I hope everyone had a great holiday week!