delayed PPD?

My son is going on seven months old. my period was delayed due to EBF for six months. I had my first period Dec 30. Since then I've felt completely off and not myself. I feel aggravated at my son more often when I rarely ever was before. I just feel tired and exhausted (not from lack of sleep). More like exhausted from breastfeeding constantly, as he still wants to latch every other hour. I feel up and down emotionally and have been making decisions that aren't quite like myself, such as drinking with friends during a night out and almost leaving with an acquaintance from my job. I just feel totally overwhelmed my emotions suddenly and I never felt like this until now. Has anyone else experienced this with the return of their delayed period?