Beginning with assessing for any medical issues is important. Also being able to pinpoint any other reasons (triggers) in your life, present or past, is just as important.
It's a bit of a process of elimination.
If your diet is of a healthy nature; your medical tests are coming back negative for any obvious health issues, that's a good starting point.
Maybe going out with your mum, recently, provided you with a distraction from the anxieties you feel when in the home. Do you feel isolated at home?
For some people, leaving the home can trigger bouts of anxiety - getting out of their comfort zone. But for you, going home seems to have the same effect.
Maybe working with a therapist, finding 'things' that trigger the anxiety in you; confronting them in a safe way (desinsitizing) gradually can help.
I think you're doing the right thing by yourself by consulting a doctor as part of the process getting to the core of your anxieties.
If the companionship of your mum or other trusted friend helps alleviate the anxiety, keep that going in your life as a valuable support mechanism, till you get the answers you seek.
As far as the tiredness goes, imagine the mental effort that goes with bouts of anxiety - it's bound to have a flow-on effect to the physical self. Experiencing and fighting the anxiety is an energetic exercise. Our bodies seem to respond with a "stop-work" reaction sometimes, to gather lost energies.
I wish you well in getting 'on-top' of how you're feeling. Remain focused on that 'mission' and don't 'punish' yourself for feeling something is not right at the moment.