Tomorrow my mother will be traveling to Algiers because she's sovery sick and she thoughtbelieves she's feeling exhausted because of the medeicin that's reason she always feels exhaustede she's taking. Tomorrow my mother will be traveling to Algiers because she's very sick and believes she's feeling exhausted because of the medicine she's taking.

The beginning of the sentence is fine, but the end starts to sound a little unnatural.

Tomorrow my mother will be traveling to Algiers because she's so sick and she thought because ofthe medeicin that's reasone was why she always feelslt exhausted. Tomorrow my mother will be traveling to Algiers because she's so sick and she thought the medicine was why she always felt exhausted.

Tomorrow, my mother will be traveling to Algiers because she's so sick, and she thoughinks that because of the medeicine, that's the reason she always feels exhausted. Tomorrow, my mother will be traveling to Algiers because she's so sick, and she thinks that because of the medicine, that's the reason she always feels exhausted.

I changed “thought” to “thinks” because it would be more accurate to use the present tense.

Tomorrow my mother will be traveling to Algiers because she's so sick and she thoughtthinks she always feels exhausted because of the medeicin that's reason she always feels exhaustede she's taking. Tomorrow my mother will be traveling to Algiers because she's so sick and thinks she always feels exhausted because of the medicine she's taking.