The spotting you have now could be due to a breakthrough. Since you are in the mid-cycle, no further comments can be made. You may have to wait until your next period and get a pregnancy
test if you miss it. Changes in body weight can make the body need more amount of hormones when imbalance can be expressed in the form of such spotting. Please make sure that you maintain a healthy body weight. See your consultant for further guidance. Good luck.