Hello and welcome,
Someone else here (who has not been posting lately and was not on MTX)
Lupus affects her blood, so her blood counts go low.

On the other hand, some here on MTX mention that the first 24 hours is the
worst (after the injection), so maybe that's when their blood counts go
low, so thanks for the heads up.

It does say leukopenia here (whiich I think means low blood counts)
http://www.rxlist.com/cgi/generic/mtx_ad.htm
In general,the incidence and severiity of acute side effects are related
to dose and frequency of administration.

Side Effects with methotrexate
The most frequently reported adverse reactions include ulcerative
stomatitis, leukopenia, nausea, and abdominal distress. Other frequently
reported adverse effects are malaise, undue fatigue, chills and fever,
dizziness and decreased resistance to infection.

Other adverse reactions that have been reported with methotrexate are
listed below by organ system. In the oncology setting, concomitant
treatment and the underlying disease make specific attribution of a
reaction to methotrexate difficult.

Hello.
I see you also have scleroderma and Pulmonary Hypertension and Raynaud's
and Dermatomyositis.
On oxygen all the time eh?
My lung function is not good and my fingers go blue a lot these days.
I've had Raynaud's since childhood (secondary I think) due to frostbite.

Keep in touch and let us know how youre doing, ok?
Hugs
J