10 ng/dl is VERY low. I doubt that on injections, levels of T will increase. Are you taking E. Cypionate injections or E. Valerate? I personally don't like Cypionate much.
Also, one needs to be sure the injectable dose is equivalent in the sense that levels approximate the average, between highs and lows on sublingual. Perhaps check levels just before next injection.
On sublingual, there is no point measuring estradiol levels as they fluctuate way too much between maximum and minimum, in as much as 10x less or more in a matter of a few hours.
What may be happening is that with injections, your levels are significantly lower than what they were when at its peak sublingually...so perhaps you should have stayed with sublingual or injection dose should be increased. Also, you could wait it out as levels gradually increase and become steady after a few weeks on injections.
Discuss all this with doctor and see what happens on your next appointment.

They will know what to do.