Sounds like hypothyroidism... You should look up all the gazzillion symptoms online, see if it fits the bill (everything from unusual wt gain(like gaining w/out eating more or changing anything), to heavy periods, intolerance to cold, loseing hair, low limbido, excessive fatigue, ... There are like 30) and it's almost impossible to get preg while hypo. It's the thyroid not producing enough of something that converts food into energy, and it effects almsot your whole body- growth hormones, sex hormones, all hormones... It's pretty horrible to have it out of whack. It can be like you're a different person.
Good luck! Hope that helps, I recommend you at least look into it online