Polly, IMHO, that's a dangerous thing to be doing, using Methylprednisolone (methylprednisone) to stave off a cold and the doctor is not doing you justice.
The conditions the corticosteroids are used to treat are much more severe than a common cold. They can also cause you to become diabetic, particularly if you are predisposed to diabetes.

I'm well versed in their use because I used high dose Prednisone for some time and then switched to high dose Methylprednisolone use for treating the cancer I have. I was on them for seven or eight years and I'm currently on a completely different schedule with Dexamethasone, about 10 times more potent.

Additional Side Effects :
1. Nausea, vomiting, stomach irritation. Take this medication with food or milk. If these effects persist or your stools become black and tarry, contact your doctor.
2. Headache, dizziness, insomnia, restlessness, depression, anxiety, unusual moods, acne, thinned skin, increased sweating, increased hair growth, reddened face, easy bruising, tiny purple skin spots, irregular or absent menstrual periods. If these effects persist or are severe, contact your doctor.
3. Skin irritation, itching, or swelling. Contact your doctor at once.
4. Long-term therapy problems: weight gain, swollen feet, ankles, and lower legs; muscle pain and weakness; eye pain; vision problems; puffy skin; a cold or infection that lasts a long time. Contact your doctor.