Missed period last months and very light period this month

Hello everyone I missed my period in December and I'm 39 i have never in my life missed a period. I track my periods with this app (glow) and it's been pretty accurate.

So January rolls around and on the 15 i start to spot and it last 3 days. On my cycle i normally wear a super tampon and a overnight pad and I would still end up messing up my panties. Also I normally go for 7 days.

This month i probably only used 2 maybe 3 pads my whole cycle and they weren't even full. You couldn't even see the blood through the back of the pad (I'm pretty sure you'll no what i mean. Like when you taking the pad off to throw it away and you can see the blood through the back of the pad). So it was like I could have just worn a panty liner but I didn't have any.

So when I went to my app and I just put that my period did start for the month of December (even though it didn't) I just wanted to see when I was suppose to have one in January and the date it showed me was that I was suppose to start on the 15 but that was no way near a normal cycle for me.

Have anyone else experienced this? And if so what was the outcome? Were you pregnant or not?