Hey everyone, I just had a rather nasty experience and now I am freaking out. Please respond

I am a "milk addict". I always chug my milk and drink around a gallon every day. Anyways, I was about to finish one carton. It tasted good, didn't smell, expires in September, and looked fine. However, one thing was at the bottom that made me freak out. There were small chunks at the bottom of the milk carton. Not exactly chunks, but thick paste-like areas of milk. I think I swallowed some of it, and then I realized there were chunks and spit the rest that was in my mouth into the sink.

I have so much anxiety right now. I feel like dying. Also, before, this was foolish, but I poured milk from the cup back into the carton, as I poured too much in the cup accidentally... I was thinking it may have gotten contaminated, forming small chunks of paste... Please help guys, I feel like v* from the anxiety.