I would start with piracetam and ALCAR. And some choline on hand, in case you need it. Good basics, and should increase your alertness and get rid of some of that brain fog. Reactions are individual, but this is a good place to start. You could add some aniracetam in if you have a little extra money. I wouldn't buy alpha GPC, it looks good on paper but is very expensive for not much noticeable effect.
Hup A and selegiline are a little more serious. I would wait and see if/how easier options affect you first.
Augmenting memory is difficult. Since you mention comprehension, it's possible that your difficulty is with paying attention adequately. If you're not alert and engaged in the learning, you're not going to remember it later. Remember to work on your study skills; nootropics are just a band-aid if these are not optimal.
I'd do some reading through other "study stack" threads. This gets asked so often that you're probably not going to get a lot of replies. Good luck!
Thank you for your suggestion, never thought about using ALCAR.
I know what you mean on the Hup A and the Selegiline. I just felt like it was worth mentioning and worth consideration.
I would highly recommend cutting the caffeine, I felt like it was keeping me going during a period when I always felt tired, but the more caffeine I used the more tired I became, I was probally using +500mg every day, and was really losing mental performance similar to your description. I have heard similar stories from others. It takes about a month to get over the stuff, so if you decide to do it time it into your uni scedule. Dopaminagenics are proballly better than caffeine but require support.
I always felt i need to work my legs to get the hormone response? whether it be anareobic run or squats or long hills runs.
Agree with crono's comments, You sound like you sliding fast maybe mild excitoxicity also have magnesium 500mg+, proanthocyanidins(pine bark extract), curcumin, green tea polyphenols, GD multivitamin, alpha lopoic acid at night. Do all of these there cheap from Purebulk.
I know they sound abit Tree Hugger but they really allow your natural system to run harder, also you will need them before you add anything more interesting.
Once youve got the healthy bit down, no caffeine then maybe some of the harder stuff like hydergine, deprenyl,d-amphetamine,donepezil(low as dose),modafinil, all of these can be got from a doc if you know how to talk. Docs would prob give you adhd script if your doing well at uni but have alot more potential, make them like you. You could try oxiractam straightoff the bat, I would keep away from aniracetam
At first I was thinking about cutting the caffeine intake, but at times I feel like I can not operate without it, especially during uni (night courses).
I may have to try to stop it during the summer time, since if I cut it out now it may cause problems?
You are correct partially on the legs part, where it releases the most testosterone. But bench presses and pull ups (big muscle groups), offers a testosterone release as well.
I think I should start taking a multi vitamin, curcumin, and start drinking some green tea asap.
I did try the doctor thing but perhaps I am not as convincing. Would try a bit more within the future if I feel like I am degrading mentally. To confirm on the ADHD medication, it is in reference to Adderall correct?
Yes, I also meant to ask about sleep. Are you getting enough? And that is quite a bit of caffeine. Maybe think about tapering down a little bit. It sounds like you have a lot of things going on which would compete for your time. Are you getting enough time to wind down? Are you stressed/burned out?
Not sure why you should "keep away" from aniracetam. You can find negative responders to any of the racetams here. I mentioned it because it's a confirmed ampakine, and as such might have more of an effect on memory than the others.
Agree with crono's comments, You sound like you sliding fast maybe mild excitoxicity
Just to be clear, I don't think I said you were sliding fast, or that there's much reason to suspect excitotoxicity here. And almost all of those "harder" nootropics have factors attached which make it desirable to seek other options first. Just my opinion, but new member threads asking for basic starting recommendations may not be the place to "think out loud" about all possibilities. 
Sleep is not a huge problem, I do try to get a minimum of 7 hours.
I do feel a bit of stress at times, but nothing major or of big complaints.
Seems like to fully understand which racetams would work for me, however, it does seem piraracetam is generally working for others. So If I were to use a nootropic stack, I would use it as my base.
I really want to thank you guys for your help, suggestiong, and time in reading and replying to me.
