Lost 30 lbs and what to gain some back.

At the begging of the year (January), I visited my doctor for general check up. There, he told me my A1C was 5.7 (considered pre diabetes) and my ldl cholesterol level was 130 (considered elevated). He pretty much told me to watch my diet and exercise. Before this, I would do some weight lifting 4-5 days a week no cardio. Being the worried person that I am, I started to run. I was doing 2 miles on Tuesday’s and Thursday’s, maybe a mile at times, on the weekend. Fast forward to August, I went back to get my levels checked just to make sure they were getting better with me exercising. I was somewhat surprised to find out they where some what the same. I did however, lose 10 lbs. Losing weight, was not my main goal but I expected from me running. So my doctor tells me to watch what I eat. I completely went cold turkey on all the junk food and eating mainly beans, oatmeal, chicken, and fish. No chips, no candy, no sodas. I expected to lose more weight from this, which I did. I was now at 166 lbs. This happened after 3 weeks of changing my diet. So I figured I would stay at this weight being that I was not changing anything else. I was exercising (cardio) and eating healthier. Well I lost 8-10 more lbs, so my weight fluctuates from 156-159 lbs. Is it normal to lose so much weight?? I’ve stopped running for a week now and trying to eat a little more carbs than before. I just had my red meat and fast food meal during last week, since August. I’m trying no to gain some weight back (healthy) .. don’t know how long it will take to see any gains. Any helpful tips will help.