Will I do jail time for a first DUI offense?

I took attention deficit hyperactivity disorder medicine. I went to a friend’s house during the day and had a couple beers when I got there. I hadn't had anything to eat all day because of my medicine. Had a beer later that night and a shot of alcohol. I've never drank on my medicine, which it ended up making me very depressed and I noticed the time and I had to be home. I was pulled over because my tire touched the white line around a curve. I passed the sobriety test but failed the breathalyzer with a .98 I think. They never told me what I blew. But I think I overheard one of the officers say .98. I've had a couple speeding tickets but nothing this serious. I've never been in trouble with the law. I don't know what to do/expect. I just know from what I've read it seems likely that I'll do six months in jail because Missouri has some of the harshest DWI/DUI laws. I'm also 25 years old. I don't know what to do. The shame and disappointment I've brought on myself and family members is almost impossible to bear. The thought of me doing jail time would be absolutely devastating to me and my family.