First off, I have always had a long cycle, and it varies some, so I have taken pg tests lots of times just to be sure. It wouldn't hurt to wait a couple more days and take another test, but most likely it will be negative too, and your period will start any day now. If I get worked up about it, it won't come until after the test, that's the one thing I can count on!
But there are 2 flags I saw in your post. First, you were on the pill. Second, you have a weight problem. Both of these can be related to/cause hormonal imbalances that in some cases most MDs might not even consider to be problems, but that you might benefit greatly from treating. I've been reading "What your doctor may not tell you about breast Cancer," and it has a really great rundown of the basics of women's hormones, as well as some discussion of the effects of synthetic hormones and other environmental factors on our hormonal balance. I'm starting to recommend it to every woman I know, regardless of their risk of breast cancer.
Last, if you do conceive while you're still heavy, may I recommend the Topeka Birth and Womens Center. I drove 80 miles to have a vbac there, and it was worth every drop of gas and every minute on the road to birth there instead of a hospital. They have a fabulous staff who are great at helping you to birth in the best possible way, without making you feel flawed or inadequate to birth your baby without medical intervention.