Getting there. Yr levels remind of mine for a while after diagnosis. Can be frustrating not to see them drop faster, and to go up after going down, but it takes time & you'll get it sorted.
The biggest single thing for me early on was cutting back on bread; amazed at how much a piece of wholewheat toast could screw up my BG for the entire day.
EDIT: Just because I always find it useful & interesting to see what other people have done, this is what my daily avg BG levels have looked like since early June:
I only started regularly testing at that point, after diagnosis in late March, when my daily avg would have been say 14-15. March through early June was my cut-the-c**p period, also on low-dose Metformin.
Up to early July was my replace-bread-with-nuts period, also the period when I'd started full-dose Metformin & that was kicking in. The ups & downs were frustrating but the overall trend encouraging.
The next couple of months or so were basically marking time with no major changes to anything; still frustrated with the ups & downs at times but basically OK.
The latest down-trend has been my fibre-is-magic period. Looking at my diet I noticed I wasn't getting enough fibre, partly as a result of cutting bread etc; increasing it seems to have had some good benefits.
This is just me, and you sound like you have to deal with much greater restrictions than I do, so just as a little illustration, not supposed to be guidance, which anyway I'm completely unqualified to give. Have you talked with a dietician at all?