Is a 10 day luteal phase long enough?

I tested yesterday at 10 dpo. I really believe I saw a faint line so I was excited to test again this morning. Late last night, I started spotting. Not brownish or pink but red. Nothing this morning but my temp dipped some this morning. Not all the way to where it normally does when AF shows but it still dipped. I took another test because I was just hoping but it was a BFN. If I started AF, it means I had a 10 day luteal phase. Is that long enough? Wondering if I maybe have an issue with progesterone production. Anyone have any thoughts for me? I'm so down right now, I don't know what I would do if I didn't have support from you all. I appreciate any words of advice. 😘