@mince3point14159265 after 3 pens, and if you're finding it harder then I would move up. I felt the same on 5mg - and decided I really shouldn't be finding it hard so moved up. But I moved up over 1 pen. Basically used a 5mg pen and upped my doses every week, using my bonus dose. So, by the time I got my first 7.5mg pen I was nearly at that dose
IMO the jabs are supposed to be helping, and there is no point in paying for them and finding it hard work still. It's now SIX months that we've been doing this, and as @UnderandOverwhelmed says, that is a long time to be reducing your food intake. As long as you are not losing too fast, I think take all the help you can get 🤷