Joint Pain, Muscle Twitch, Feeling Cold, Weight Gain, Mood Swings, Tired. Done TSH Test. Hypothyroidism?

Question: I am writing to inquire about the possibility of a thyroid issue. Symptoms I've been experiencing (pertinent or not I'm going to list): achy with joint pain, continuous muscle twiches in my calves (which I asked my MD about and he suggested to increase Ca and Mg which I have and it continues regardless), periodically throughout the day muscle twitches in my eyes, mouth, hands, frequently cold when others are not, weight gain (around 5 pounds), mood swings, and most concerning is being extremely tired in the last 3 weeks (to the point where I feel my work is suffering and I look forward to going to bed all day). I do not feel depressed in any other sense other than frustrated/down about not having enough energy to carry through my normal routine. I also endured my first menstrual period 16 days ago (7.5 months postpartum third child still breastfeeding) which was the heaviest flow of menstrual period I have ever had. I had a TSH done in May of 2011, routine, and it was 2.0. I did an at home test for TSH last week due to being so exhausted and the result was 4.2. I realize 4.2 falls into the "normal" range on most of the references you read, but also am reading some reference to 3.0 possibly being the top end of "normal XXXXXXX All this considered, does hypothyroidism sound like a reasonable explanantion? Any other ideas regarding my symptoms, most specifically the extreme fatigue? Thank you for your time.