2 light cycles in a row within 2 weeks apart?? what's going on???

So basically my period has always been like this: the start date would vary and is typically late. But the cycle itself has been consistent Day 1: would be cramps and medium flow, Day 2 would just be a ridiculously heavy flow, then Day 3-5 would be light. 
But now things have gotten weird. I guess for one, my cycle in April
 started 2 days EARLY before the exact month anniversary of my precious start date, which I thought was weird, but I shrugged it off because I thought it would be a one time thing. 
On the next cycle, the same exact thing happened, except my entire period was LIGHT with some spotting after the cycle ended. Which has never happened so I was thinking that it was sketch, but I decided to see what happens in the future before I do something about it. 
Now, fast forward to today, a little over 2 weeks after my period ended and I start AGAIN with a light load again! 
Like wtf is going on?? It would've made sense if it was because I was stressed  on my precious cycle because I was finishing up my freshman year of college. But I'm home for the summer now. I am on Welbutrin but I  started taking that on January so why would my period get weird now? Are there any other possible causes? Should I wait until I see my psychiatrist when I meet with her for the first time or should I contact my Dr ASAP?