well all i can say to you is try and relax a bit more find things to occupy your idle time and do more things with your partner , and dont stress, i know its hard , i also thought i had a problem at first after the 1st three months of nothing happening and i am still fairly young - and guess what i am 4 weeks and 2 days pregnant
i got a ver faint line , which my husband told me to dis regard but i read on the internet that any line at all within the time span given on the box is a positive so i left it and tested 4-5 days later this time the line was still much lighter than the control line but it was a positive and i have not got my period , mild cramping no spotting , so hang in there it will happen you have had 2 kids so you know its not a fertility issues its probably more emotional and has alot to do with your mind set.

good luck and just enjoying making the baby