So first things first...Tell your co-worker she makes you uncomfortable. Straight up and in the moment. I had a similar situation when I was younger with a boss. He was a straight up creepy pedophile and when he patted me on the head for a doing a good job, I straight up looked at him and said, "When you touch me like that it makes me very uncomfortable. Please dont ever do that again." That cleared the issue right up and never had a problem since.
Secondly, my .02 about getting back together with your ex is that you arent together for a reason. Use this time, like you said to regain your foundation, get clear on what you want out of a mate, and then go out and get it. Getting involved in seeing/dating someone else after a break up is never a healthy decision in my experience. Just a distraction. Which once that fling is flung, will lead to the need for another distraction.
Focus on you. Then your plan of action will be clear.