Deep breaths,
@Jazz97 , deep breaths!
28 is obviously too high, but provided the ketones are in range and you have insulin in you, it's not dangerous, but do keep an eye on the ketones.
You'll presumably have injected for the meal, so have a think about the amount of insulin you took, how many carbs were in the meal and where your bg was at before the meal and then discuss with your dsn how the dose size can be adjusted.
It's not a failure - it's just part of the learning curve which we all go through. After a while, you'll have learned from mistakes, and be much more confident in saying, ok, that meal will need x units.
Maybe too early for you to try this just yet, but a lot of us find that 'pre-bolusing', injecting a while before the meal, usually about 20 mins or so, gives the insulin time to get to work before the food digests.
People new to this often experiment by eating the same meal a few days in a row and starting with a 5 min pre-bolus and adding another 5 mins to find their sweet spot. I could eat a 70g meal and if I didn't pre-bolus I'd be away up at around 15 or so, but with a 20 mon pre-bolus, it'll barely touch 7.
Like I say, though, it does take a bit of trial and error - there's been a few occasions where the insulin has kicked in hard long before the meal has turned to glucose and I've ended up a bit hypo before the food has caught up. Brown rice and pulses can take a while to digest, so I'll normally reduce the prebolus timing for those down to only about 5 mins or so.
You said you tested about 2 hrs after the meal? Bolus insulin tends to be active for about 3 to 5 hrs, so it's likely that the remaining iob (insulin on board) will still be working, so it's probable that it will drop, but you won't know for till about 4 hrs are up.
Testing after 2 hrs is more of a T2 thing - what's more important for T1s is seeing how it's played out at the end of the bolus activity about 3 to 5 hrs later.
One of the most useful things to know is how much insulin you have on board. Some meters do that, and cgm apps like the android one xDrip+ do it even if you're not using it as a cgm.
For example, if I was sitting at 10, 15, 28 or whatever, if the iob indicator on xDrip+ was telling me I only had 1 unit iob, I'd be saying that's not enough to bring me down and I'd do a corrective shot to lower it, whereas if it said 6u with 3hrs to go, I'd say, ok, that last shot is peaking, still a fair amount, so I'd leave it to see if it drops ok.
I'd be tempted to wait till about 4 hrs after the meal when the last injection has more or less run its course and see what it looks like then.
If it's still very high, you might want to think about a correction dose - taking a few units of fast acting insulin without food. We can't advise on doses, it's something you'll need to experiment with as we all vary.
As a very general starting point, official courses like DAFNE teach that 1u will drop by about 2 to 3. But at very high levels, insulin has a difficult job to do before it drops. Although we can't advise on doses, if you're still at 28 after 4 hrs, you've got safe room to experiment with corrective doses without getting anywhere near a hypo, and remember that if you overshoot with the size of dose, some lucozade will sort it.
Yes, it can be a scary situation, but, believe me, it does get a lot easier when you become more familiar with how insulin works. I'd highly recomnend getting cgm - being able to actually see how your bg is moving makes it a lot easier to "steer" it instead of the guesswork which strips involve.
Here's where to get xDrip+ if you want to have a go with tracking iob:
https://github.com/NightscoutFoundation/xDrip/releases
Click the "Assets" tab and download the .apk file.
You need to go into Settings/xDrip+ Predictive Simulations Settings to switch it on.
Good luck!