Could NuvaRing stop my period from coming down?

Hello. I haven't been off birth control for almost a year and a half now (mostly because I couldn't afford it). However, a few months ago I finally decided to make birth control a priority and got a prescription for a NuvaRing. I loved it because I'm the type of person who'd most likely forget to take a pill one day or even two... but I digress.

On beginning the NuvaRing, the instructions state that, if inserted on the first day you'd have instant protection. Well I was at the gym working out with the husband and, when I went to the bathroom at the end of the workout, I saw that my underwear was pretty stained (as if a tablespoon of blood had been spilled on it). Naturally my husband and I were excited and whatnot especially after the long waiting game for my period (we had kept the NuvaRing in storage and my irregular period cycle made this an unbearable wait).

The second we got home I slipped in the NuvaRing and had unprotected sex. That night I had the mother of all cramps and had to be massaged to sleep. I inserted a tampon and the next morning the bleeding had only filled the very tip of it. It's as if the bleeding went from full-on to not-at-all-there overnight. This is very strange for me. Usually I have a light day, followed by a heavy day and then 2-3 light days again.

So now I'm freaking out because my period stopped, something that I don't remember ever happening, and I had unprotected sex. I had the typical things that happen during a period occur. Namely, I had an acne breakout, had cramps, had vaginal dryness as I usually do on my period, and had a period-like "scent." However, no blood came down after that day other than turning some toilet paper slightly pink the day after when I went to the bathroom. What I'm really afraid of is that I didn't, in fact, have my period and that there's a possibility that I may be pregnant.

Anyone have any thoughts? Did I  jump the gun?

[itsmybirthday]

Nuva ring can cause you to have shorter, lighter periods. That's one of their main advantages. You're probably fine.