Fatigue-is it the Herceptin, the Tamoxifen or both?

[Sundrops]

I was diagnosed with IDC and HGDCIS in 2024, since then I've had surgery,chemo and radiotherapy.
I'm now on Tamoxifen for 5 years minimum, been on these maybe 8 weeks so far, and also continue to have a Herceptin injection every 3 weeks for the next few months.
Over the last couple of weeks I've been hit with the most exhausting fatigue but unsure what's causing it,if it's more likely to be one of the medications or maybe the combination of both?
Has anyone else experienced this?

When did you finish chemo? You are bound to be tired for a bit.I’d see GP and ask though. Mine gave me vit D and it helped alot. I didnt have herceptin but did have tamoxifen and chemical menopause. The whole thing is knackering tbf