When to go to the hospital...and other concerns.

Hello everyone ^_^ I had a quick question for all of you ladies who have probably been in a similar situation before.

My obgyn, and the hospital where I will be giving birth, is about a 45 minute drive from my home. If I start feeling contractions, how close together do they need to be before I head for the hospital? Most things I have found say go to the hospital if they are 5 minutes apart for about an hour or something similar. I am just concerned because of the drive but that is probably just me being silly.

My other concern needs a bit of back story though lol

With my first, I went into labor at 35 weeks and I never knew I was in labor! I had an appointment with my obgyn but I wanted to go shopping before hand. So for about an hour, maybe an hour and a half, my mother and I were walking around shopping for baby clothes. I go to my appointment and my dr checks my cervix. He goes really quiet and leans against the counter. At this point I am confused. He asks if I had been experiencing pain or cramping and I said no. He asked if I had been bleeding and again I said no. Now I am panicking. He calls the nurse and then tells me I am already 6 cm dilated and I need to get to the hospital. I was checked in to my room at 2 pm and by 8 pm the same day I had my daughter. I never felt a contraction until I was given pitocen and even then I barely felt them. I had an epidural and definitely couldn't feel the contractions. I couldn't even feel any pressure when they told me I needed to push. After about 20 minutes of pushing my daughter was born but the doctor found out my placenta was imbedded. Removing the placenta was the most excruciating pain I have ever felt in my life. My new dr said he would put me out to remove the placenta this time instead of reaching inside and scraping it all out while I am awake.

I am worried that once again I will feel nothing and end up giving birth in the car or having complications because I can't tell that I am in labor. Has this or anything similar happened to anyone else? And advice is greatly appreciated.