Hi Liz! Yes I can see the SS now! Thanks.
The DM dry food you are feeding is 13% carbs so that will keep the blood sugars up higher than they need to be.
Diabetic cats need a low carb wet, canned diet with carbs under 10%. Having the carbs around 5 % is better.
It is not necessary to have a prescription diet for a diabetic cat....they are expensive and are mostly too high in carbs, and the content of the food is not any better than most canned food you can buy over the counter.
Dry food is very bad for cats. It is not only high carb, it is much lower in moisture, around 7% compared to 78% for canned food. Cats need lots of moisture for their kidneys and general health.
Here is a link to suitable foods. I'm not sure what country you live in so I will give you a choice so you can pick. Hopefully your country is listed.
If you transition over to a low carb diet you should see some lowering of the numbers.
However you need to do it slowly and test frequently as the BGs could drop up to 100 points.
http://www.felinediabetes.com/FDMB/threads/links-to-food-charts.174182/
Lantus is a great insulin for cats, but it likes consistsncy. It is a depot insulin, which means it leaves part of its dose in the body to be used later and it takes up to 6 cycles for the depot to fill. Chopping and changing the dose messes with the depot and the BG numbers.
Depending on what dosing methods you choose, we recommend holding the dose for 3 days (tight regulation) or 7 days (SLGS). You can read about the dosing methods at the top of the Lantus page in the yellow stickies and choose the one that suits you better. I would recommend you choose a method to follow as you will get better results.
We also recommend only increasing the dose I/4 unit increments at a time so we don't go past the best dose.
Always test before every shot to make sure it is safe to give the shot.
We all make mistakes so don't beat yourself up about it. You were trying your best after getting bad advice from the vet about the dose.
I think the first thing you should do is look for some suitable low carb wet foods and start transitioning over to them slowly over about a week or 10 days. You will need to be testing frequently during this time and adjusting the insulin dose if needed.
If you post each day and keep the SS up to date, we can help you with that.
We also recommend giving several smaller meals during the day and night. A meal preshot, then a snack around +2 or 3 and another snack around +4 or 5 each cycle. A timed auto feeder is a great investment.
Then after you have swapped over to a fully low carb diet, we can see how Snickers is going and decide what needs to be looked at next. It's best to only do one thing at a time. How does that sound?