Keeping Track

I'm not so sure buying a scale (the first I have owned since before I had my daughter who is 11 and when I had an eating disorder and weighed a measly 111 lbs!) Now tipping the scales at 160 on some days and 156 on others I wonder if its really necessary to know my weight? I've noticed that my weight fluctuates daily and depends on the time of day and some mornings I'll weigh 4 lbs more then the previous one and then vice versa with no real understanding why!! Anyway I can tell I'm starting to lean out from my December extra eating and my ASS is sore every day. Will there be a day when my ass isn't sore? I don't recall it hurting this much last season! WTF! I am running a 5K this Saturday for Haiti Relief and at least feel like I can give back in some positive way. I have sprinting on the track at Flamingo Park when i'm in SoBe, but have still been unable to find a running track in Fort Lauderdale for the times I'm in that area!!! Is it too much to ask to have a track accessible to the public?