Hey everyone. My question today is, is it normal for blood sugar levels to go up to as high as 350 after drinking a soda? And is it normal for blood sugar levels to get as low as 50? Iām a bit new to this, thanks. 
Normal blood sugars are between 70 and 120. For people with diabetes, the goal range should be between 70-140 (going up to 140 after meals is normal for many of us).
As someone with pre-diabetes, if you are seeing numbers as high as 350 and as low as 50, you should see a doctor right away! Are you taking any medication for your diabetes?
It would be quite strange to go as low as 50 unless you are taking medication. I think the only people that usually see such big swings in their blood sugar are MODY diabetics which is a genetic form of diabetes. You can read some information about it here.
I think that you should go see a doctor if at all possible. Also you can write more details here about when you have the highs and lows and we may be able to help you!
Was the 350 after drinking regular or diet soda? You should not drink regular soda or fruit juice anymore as those have very high amounts of carbohydrates.