Hey Dan, it's great to hear how much running is helping you. If there's one tool I swear by it's definitely some hearty exercise. Great for your mind and body. Just keep up with it, and hopefully you'll naturally quit smoking. So long you're scaling back it's a good start, although I'm one of those odd people that believe if you can become and excellent runner and smoke (in moderation of course) if you want to.

As for working on speed and letting muscle develop properly, it's going to take time since you're only on day 9. You're making solid progress so far. Just keep that in mind and don't over do it or you're going to get classic burn out. I know it's hard as hell when you use to have a different level of fitness, and then when you start again it's almost like learning to walk all over again.

Make sure you're eating properly with enough protein to back up muscle development and lots of fruits and veggies that are high in vitamins and minerals (especially vitamin C and potassium). Yogurt is also great. I also use some supplements for health in general, but I feel like they help my running a bit.

A good way to increase your speed is vary your distance and pace day by day. Do 2.5-3 miles one day and focus on keeping speed, then do one mile the next focusing on bursts of speed (sorta like interval training). If you do this, it'll help increase your speed while maintaining and building upon your endurance.

Did you use to do martial arts? Consider starting martial arts again. It's an amazing way to exercise, and running compliments it beautifully. Furthermore, many martial arts come with a philosophy that help further your mind and soul. Even if it's not a traditional martial art, training will simply give you a lot more discipline and focus. I recommend it to anyone who enjoys exercise, especially if they deal with mental health as well.

Keep up the good work!