ttc difficulty

hey all. so, I've been off birth control since December. we have been trying to concieve to no avail.

when we tried with our son, literally it happened within the first month. I guess that gave me false expectations on how easy it should be.

well after we had him about a year later we tried again twice, both miscarriages... and those pregnancies didn't take long either.

now we are trying again. but can't get pregnant.

my cycle is 25 days.. kinda short.

anybody have any advice to help with fertility?? any inklings as to why I'm having trouble?? first pregnancy was easy peasy except for gall bladder had to be removed.