Part-time dieter

So far this bridal diet thing has been 2 steps forward and 1 step back.  But not for the obvious reasons, let me explain:

Since January MJ has been living in Santa Clara and I have been living in Sacramento.  That's distance of roughly 2 hours (depending on how fast you drive, it could be 1.5 hours, which it usually is for me) which has caused some changes in our living conditions considering that we were living together for almost the last two and a half years.  I had to stay in Sacramento so I could finish my last semester of school and he had to move to Santa Clara for a major promotion at work (I am very proud of him, he's an awesome manager and overall business genius) and rather than renting two apartments, he moved to SC with all of our things and I moved in with my mom, back into my room that I had as a teenager.  

While I've been at my mom's house, she makes most of my meals (she's been referring to me as Oprah lately, LOL) and then on the weekends, when MJ and I are in Santa Clara, we pretty much totally veg because the week seems very long with the extra driving and both us missing each other a ton.  Long story short, I eat healthy and am totally good on my diet Monday - Thursday and then when MJ and I are together again, I basically eat like a man.  Well a man exploring new restaurants in a new town.  For example, I had a Double Double from In-n-Out Burger at 11:00 this morning.  If MJ and I were living together like normal, he probably would have made us a cute little Sunday morning breakfast because I would have gone to the farmer's market like I used to/normally do on Sunday mornings.  Instead, there were no groceries in our house and on our way to McDonald's we spotted In-n-Out, enter the Double Double, fries and diet coke.  

So basically I'm postponing this whole Wedding Dress Diet thing until July when we will be living together and have some normalcy in our lives once again.  The upside: I won't stress on the weekends about what we're eating, instead I'll just enjoy the new restaurants, food and spending our little weekends together; plus I can continue to be good during the week (and maybe add some extra cardio to make up for my weekends a little bit).  The downside: this will give me less time to get in shape before our engagement photo shoot in August (and our engagement party in August).  

Has anyone else tried to lose 15 - 20 pounds in a short amount of time and had success?  What did you do that brought you success?