We've been TTC, what do u think about this?

Hubby and I are ttc, I had a miscarriage on the 24th of Sept at almost 4 weeks, so the doctor said its ok to try agian so when did. We BD on all the right days(I think). AF was due yesterday but hasnt showed yet, now the only signs I have had are a small amount of lower back pain last night and my stomach hasnt been feeling right, not like morning sickness I dont think, maybe more like a full feeling and when I drunk Pepsi, I feel sick bc its like I am to full. No sore or spotting. Can anyone please to me what you think or has anyone every had this happen to them b4? Thanks in advance and lots of baby dust to all of u TTCer's!!