I Eat Breakfast Which Is Toast With Jam And Start

I eat breakfast which is toast with jam and start to sweat, and some times during the day for no reason I start to sweat for about 2 mins then it stops, but will come back in about 2 to 4 hours for another 2 mins.
My medical history is 2 transnoidal opps for petuitary tumor and 6 weeks of radiotherapy, in 2014.
had have a DVT and PE in jan 2016 follower by Cap after.