So confused! Need help

I'm 27 years old, been ttc for a little over a year now. Starting going to fertility doc last week (the day after ovulation occurred). During transvaginal US, it was determined I did in fact ovulate and I have plenty of follicles. Anyways, so ovulation most likely occurred this past Sunday or Monday. So..here's my actual problem...my bbt did it's typical rise the day after ovulation...but then it spiked drastically at 3 dpo. Then at 4 dpo it dropped drastically and then it rose again today. We bd today and I started spotting right afterwards. It's very skant and sort of an orange color. Could this be implantation bleeding?? Or is this from having the U.S.???