At my wits end .. 16 Months TTC

Hey everyone, 

This is a bit of a long one so please stay with me. So i have 2 children from a previous relationship and me and my fiance have been trying TTC for the past 16 months. Ive had 2 gyne appointments (full bloods & internal scan) currently waiting on 3rd gynecologist appointment in the next 4 months. Bloods came back with everything being fine apart from not showing signs of ovulation (only 1 day bloods were taken) and also not showing signs of pcos (was told 5 years ago after having my son, that i did have pcos as there was more cysts on each ovary then should be) When the doctor was doing the scan she said she saw a small sack looking thing, my fiance also saw this twice (he said it looked like it was jumping around the screen lol) she couldnt find it again but she did ask me when i last took a test (the morning before scan) then said to me i should take a test in a week as this could be an early stage of pregnancy .. has this ever happened to anyone else before? Also was told to lose more weight from now until my next gyne appointment. Now ive lost 2 stone and BMI has dropped down to 30 since September but i just feel like my weight is always an excuse. Yes i do need to lose weight, but surely it cant be down to everything? The reason i say this is because ive not had a period since last July, ive always had irregular periods before but always had more then 9 a year. Im at my wits end with it all. My fiance is waiting for a referal from his gp for a SA, we both dont drink, dont smoke, have sex every second day, eat reasonably healthy, only thing we need to work on is weight but i do exercise reguarly. Does anyone have any advice or have been in a similar situation? Im really worried due to having no periods. Also being doing ovulation test’s every day for the last week but all come back saying negative 😞 Thanks X