Miscarried, got vaccine, and now this

Hi,

So I miscarried in April and got the Covid vaccine in May. And today I am on my second or third day of period. I noticed that there is light brown spotting and there's no heavy flow. Usually, on my secodn or first day my period is bright red and tends to come in normal flow. On the other hand, I am having severe mood swings and I do not feel myself at all. I am feeling confused, lost, and hopeless. This isn't me. Has anyone been through this and started having their periods back to normal?