Hi Roxi,
Hang in there. I've been where you are more times than I care to remember. The only advice I can offer is keep trying, make sure you're getting the timing right, seek out a doctor's help if possible, and pray.
Your words sum it up - I too have been mega depressed at times, wondering if my hope for a baby will ever happen. I hope it's at least comforting to know you're not alone.