HELP! When did I conceive? Anyone accidentally taking CLOMID while already pregnant?

I've taken clomid 2 cycles.

First cycle (50mg, days 3-7): I don't think I ovulated (no positive OPKs, no temp shift, no symptoms), but we BD'd days 12-16. My period was 3 days late. All preggo tests negative. Period was dark brown and heavy for 2 days (unusual for me; figured it was the clomid).

Second cycle (100 mg, days 2-6): period lightened after 4 days. OPKs were positive days 9-15. pregnancy test positive on Day 14. We only had sex Days 6 and 9-13.

I've now had 3 positive prego tests (see attached) and blood test confirming 50ml of hCG.

Two questions:

1. Has anyone accidentally taken clomid when already pregnant? Effects?

2. When is the most likely date of conception?

Ideas? Help! What is going on?