Please help

(Reposting because I only got one response)
So I'm supposed to get my period on the 29th of June. Well I started bleeding on the 18th and it was a medium spotting for like 4 days. No cramps at all. My periods are generally extremely painful and extremely heavy. Well on the 18th I flew. I get flying anxiety so I took half a Xanax which is something I have never done. Would that cause bleeding? Or was it implantation bleeding? Flying anxiety has never made my period a week and a half early before. Please let me know your thoughts! Also my nipples are sore