Birth Control

Okay so, around May 2013 I got my first depo shot. I didn't follow up 3 months after like I should've if I wanted to continue it because I felt weird not having my period every month. Also, I felt there was no point in getting it because I don't see my boyfriend often given the fact he lives about 300 miles away from me. 
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A week prior before my trip to see him for a few days I went to my local pharmacy to get Plan B.
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​In December 2013, I used Plan B about 24 hrs after unprotected sex (we used the pullout method). In addition, I still have not yet gotten my period before taking Plan B. So I got a pregnancy test a week later at my local hospital, and it showed up to be negative. 23 days later from the day taking Plan B, I finally get a normal period. It lasts 6 days. A week later from the day I ended my period, I start my period again. What's weird is that two periods in one month - only a week apart.
​I've read online that Plan B may delay or cause periods to start earlier since hormones are out of whack. I couldn't have known my normal cycle to know if my period would be late or early for the fact I haven't had it for 7 months. 
I haven't read anything about having two periods in one month prior taking Plan B. I have read two periods in one month could happen; before plan b and a week after taking plan b.
​Now I'm thinking, 'Could it also be my body reacting from the depo shot with plan b since I didn't have my period 7 months before I took Plan B even though I only got one shot?'
I mean, I feel normal. I don't feel nauseated or anything like that... So far.