Welcome to the group.
My first suggestion is that you read through the sticky notes at the top of the Board. There is an overwhelming amount of information about Lantus, dosing, and pretty much everything you will need to get you started. It will also be helpful if you could get a spreadsheet set up. This is the
link to the instructions for setting up a spreadsheet. The spreadsheet will let you easily monitor Maddi's progress and allow us to see how your kitty is doing so we can offer help based on Maddi's numbers. We are very numbers driven!
It's important that you decide on how much insulin you want to give and stick with that dose for the requisite amount of time suggested by either of the
dosing methods we use. Lantus dosing is based on the lowest number in the cycle and not on the pre-shot numbers. This is one of the major ways that Lantus (and Levemir) differ from other types of insulin.
It's great you've got Maddi on a canned cat food diet. As far as bringing the vet a urine sample, it's really not the best way to determine if your cat has a UTI. There are a ton of ways a sample taken at home can be contaminated and give you a false positive reading. You really need the vet to get a sample by drawing urine from Maddi's bladder with a needle (this is called a cystocentesis) and the urine sample is then cultured in order to determine what the bacteria is so the appropriate antibiotic can be prescribed. This is called a "culture and sensitivity."
You didn't mention when in July Maddi was diagnosed. This is a useful bit of information in that it takes about a week for the Lantus depot to form. Prior to the depot stabilizing, you may not see much of a change in Maddi's numbers. Depending on when you started Maddi on Lantus, this may be why you saw such a change in the numbers. Also, when numbers are high, it's likely Maddi is going to be drinking and urinating excessively. When you skipped the shot, that was likely the reason for the number of trips to the litter box.
In general, we don't start cats at much more than about 1.0u. (If following the Tight Regulation Protocol, the initial dose is based on your cat's ideal weight and for an average weight cat, it's about 1.0u.) We also change doses by 0.25u. You're vet is suggesting you increase by way too much. When starting out, if you are not able to monitor, we would have likely suggested that you either skip the shot or stall for a while to see if Maddi's numbers were going up. Once you have a bit more experience with managing your kitty's numbers, 150 is a very safe number to shoot. Many vets are uncomfortable with telling their clients to shoot lower numbers because most of their clients do not home test.
It actually is possible that it is a bounce. However, without being able to see Maddi's numbers on a spreadsheet and have a better sense of the pattern, I'm hesitant to say more. Bounces occur if a kitty's numbers drop low, drop lower than the cat is used to, or drop fast.
Please let us know if you have questions. The members here are very generous with their time and knowledge.