Almost anything at this stage of our lives can be "normal" and not be anything to worry about. Periods can be closer together, (shorter intervals in between), further apart (skipping months...perhaps, several), heavier, lighter....and everything in between.
The only "constant" during perimenopause is "change". :)
And, no 48 is NOT too young to be having this type of thing happen. Perimenopause can start anytime during our 40's (sometimes, late 30's) and last between 3 and 10 years.
It wouldn't hurt to keep track of this in a journal and when you get a chance, (no real rush), go and see your doc and as the previous poster has said, get some bloodwork done just to see where your hormone levels are. If you are really concerned about this within yourself, pick up the phone, call your doc and see if she/he wants to see you over this. I'm sure that it's very likely nothing at all but, a hormonal fluctuation. If it keeps happening, then it could that your hormones are a bit out of whack and he/she may just want you to keep a diary and watch what happens for a bit and do some bloodwork.
I don't think that there's anything at all to panic over. :)
Sending you my best wishes!
Your period can come and go throughout years and years of menopause symptoms (I've been in full blown meno for two years, absolutely no period and I'm only 46). I would definitely go to your doctor to have all your hormone levels tested so you'll know for sure if you are estrogen deficient or dominant.
Good luck, this stuff is pretty miserable but there's alot of help out there!