The best thing you can do is to educate yourself on the symptoms but still have a conversation with your OB/GYN to be sure. Most of the time, you can ask to speak with a nurse at an office who can tell if you need to be seen or not. Here's what Mayo Clinic says about perimenopause - it's worth reading through all of it:
http://www.mayoclinic.com/health/perimenopause/DS00554
Night sweats and irregular periods may be signs of estrogen deficiencies (menopause is marked by considerable drops in estrogen levels), but they can also be indicators of more serious conditions such as certain cancers, so I'd always recommend calling your OB/GYN's office just to be sure.
I don't want to scare you, but I've been on the receiving end of a devastating diagnosis, and if I'd not been my own health advocate and pressed when my physician (coincidentally my OB/GYN because I was a few weeks postpartum) wasn't concerned, I'd been diagnosed with a much worse prognosis.
Good luck!