Can augmentin (amoxicillin and clavulanate) cause severe fatigue and weakness?

Yes. Augmentin (amoxicillin and clavulanate) can change the microbial makeup of the GI tract and can lead to diarrhea and potentially loss of essential electrolytes, fluids and nutrients. These then can cause fatigue and weakness.
Not likely. Anything is possible, but this is highly improbable. The penicillins are among the least toxic medications you could be taking and severe fatigue and weakness is overwhelmingly more likely to be due to the underlying illness for which you are being treated.

Related Questions

Can amoxicillin and clavulanate potassium tablets treat chlamydia?

Chlaymydia. Unlikely. Penicillins work by inhibiting cell wall synthesis and inducing autolysis. Since Chlamydia has no cell wall this is not appropriate therapy. Azithromycin or doxycycline are the best alternatives. Read more...
No. No not the appropriate antibiotic. In my community the chlamydia is not fully cleared. . Read more...

Is it safe to drink alcohol (one or two beers) while on amoxicillin and clavulanate capsules?

No guarantees. There's no major interaction with alcohol. That being said, when sick (the reason I'm assuming you are taking amox/clav) alcohol can delay recovery as well as interfere with productive rest/sleep. Amox/clav is broken down in part by the liver as is alcohol, so there is certainly potential for harm there especially with excess. I would avoid alcohol until feeling well and off antibiotics. Read more...

Can I still take pill form amoxicillin and clavulanate that expired 9/15 for swollen lymph nodes?

Not such a good idea. Given that they expired over 1 1/2 years ago, I would not take them as they are partly organic molecules which can start disintegrating after their expiry date. Read more...