Very worried

hi I'm new on here. My husband and I have been ttc (casually) since jan 11th this year. Since then I have gained a lot of weight and I haven't had a period since about jan/feb time. All tests negative and I've been under a load of stress and having lower abdo discomfort, tender breasts, fatigue and mood swings. Maybe 8 months ago I experienced a pain in my lower right side that caused me excruciating  pain whenever I tried to move my leg. I collapsed, screaming, the pain was that bad. It came and went out of nowhere. NHS direct were baffled and it's never come back so severely. I'm terrified there is something wrong with me and I won't be able to conceive, but also terrified of the doctors, needles and having weight checks (I've gone from about 11st 5 to 17 stone in a year) I'm committed to losing weight but still feel really scared and alone