Clomid and unexplained fertility! Going Crazy now!

I’m on my second round of clomid..50mg and first round finally put me on a normal cycle! Well earlier this week ( Sunday to be exact) I started having the WORST back pain and headaches! I NEVER get those before a period. So I first thought maybe implantation, since I was having some abdominal cramps and a weird stomach ache and I just felt sick for 4-5 days. According to my calendar and calculations I’m due for a period tomorrow, if I stay on my normal cycle now, but I have NO symptoms I usually do. All I’m having is the light headed, back pain, extremely tired, and little abdominal pains with still feeling sick. Oh and I’m ALWAYS having hot flashes lately, when I’m usually cold. I took a test at 8-9 dpo ( couldn’t help it) obviously negative and I took a test today and negative again! I don’t wanna get hopes up, but it’s just different feeling and maybe because I really want this miracle this month. Two years off and on trying. I called my doctor and his nurse seems to think it’s definitely not the clomid. My doctor seems to think I wouldn’t need all three cycles, but here we are and I’m getting negatives! Is there still hope for me!? Anyone in the same boat? Could use some advice!