Restarting, motivation needed!

Hey everybody,
I've been active on and off on MFP for a while with varying levels of success. My longest period of time was probably about 4 months where I lost about 20 pounds and felt GREAT. This was my senior year of college. After graduating and moving around a little bit, it was extremely difficult to stay consistent and I lost track and haven't been able to get back on since. I have a girlfriend who is very physically fit (runs half marathons) and I don't want to miss out on something we can do together because of the fact that I'm just not in good enough shape to be able to do it. She is currently in vet school out of the country, so I feel like this is the perfect time for me to push to get in shape for when she gets back.

The main problem I'm having right now is that I am a very busy person. I work 8:30-5 and recently got a dog. Therefore, my routine is wake up at 7:20, feed the dog, get dressed, walk the dog, throw a sandwich together real quick for lunch, eat breakfast and leave. I have many friends so I am often getting together with one of them at night, making it difficult to really focus on cooking a healthy meal every night.

While typing this, I realize that I have to have priorities and can't let friends get in the way of maintaining a healthy lifestyle, but I was just hoping that there are others out there who have been in a similar situation as me and have some advice/tips for being healthy while also being a busy young professional.

Thanks!