Hello Alig,
you say reading are all over the place, does that mean high, low or both. Also what dose are you on and how long you been on it.
I'm on Glic, 30mg twice a day. Initially I did drop a bit low a couple of times, but seem to have settled down a bit now. Able to run/cycle/swim for at least an hour without any adverse effects, haven't tried longer yet. It is a drug that can cause low readings and hypos, especially on higher doses, and if you do a lot of exercise.
If it doesn't settle down I'd have a word with your GP. Maybe not an appointment, but a lot of surgeries offer a booked telephone call from your GP so you don't need to take time off work etc.