I Need To Get Back On Track!

I weighed the same for my entire adult life (118-120 pounds) before I had my daughter. I gained 50 pounds during my pregnancy. I lost half the weight immediately, then got down to 123 roughly two years later (which felt great and was a good weight for me). My daughter is now 11 and I have put on weight gradually over the last few years. It had been teetering around 128 for quite a while but lately I have crossed the 130 mark. I was on vacation recently and weighed myself before and during. I weighed a solid 132. When I got home last Thursday I still weighed 132. This morning, less than 4 days later, I am horrified to see I have shot up to 135!!! I have not eaten anything fatty or anything to excess nor have I had anything in my diet to warrant such a spike. A while ago my doctor said that now that I am over 40 I can expect a steady increase of weight gain, especially around the mid-section. I am not ready to throw in the towel just yet, so I must act now. I am irritated beyond belief, bummed and desperate to get all of this extra weight off once and for all. My jeans are painfully too tight, I feel awful putting a bathing suit on and I want to feel good again. Exercise has been tough due to a torn tendon in my right elbow. It's hard to get motivated while having to modify my work outs but I must do something to get back on track. Thanks to anyone who is out there reading this. I could use all the support I can get.