Why won't lymphocytes count increase??

I was told to stop Tecfidera last June as my lymphocyte count had been too low for the last 3 blood tests (18 months). I’ve been getting my bloods checked every month since November to check for them increasing enough for me to start Aubagio. Mostly they’ve stayed between 0.4 - 0.6 but March was 0.8
Has anyone else had this, why would they go up one month then back down and why a year on are they still down, 0.5 this month.
I was taken off Plegridy for the same reason 3 years ago but my bloods recovered in 3 months so I got started on Tecfidera. But this time they’re not recovering at all??
Help I’m starting to worry there is something else wrong with me!!

I am in a similar situation. Before taking Tecfidera they were well into the good healthy range. Stopped from taking nearly two years ago. Put back on after a relapse and had to come off again after another 9 months.
Slowly creeping up again until I had an infection when they plummeted.
As lymphocytes are part of the body’s defence system they are hit by infections. Told I have to get back to above .8 to start my DMT of choice.