You have or are going to complete 26 weeks of paid leave. You need more leave to make your baby comfortable. You can even resign if no extension of leave is approved by the employer. When you submit your resignation papers, the employer may very well ask for a notice period. You cannot serve the notice period; if you could, you would have gone to the office. Once you make it through the first week, you will get accustomed to it and may even consider continuing in the organization. The major question is whether the employer can demand the 5 months' salary already paid to you. The answer to your major question is NO. The employer cannot demand that you repay the maternity leave salary paid to you. If you resign now, sometimes they will retain this month's salary and adjust it towards the notice pay.
Now, coming to practical views, I would advise that you should not resign and leave. Women, being very empowered, should take it as a challenge. Obviously, if there are 50 employees in your establishment (men and women combined), you can demand a creche and have the opportunity to visit your baby and feed him/her four times during an 8-hour period. This can solve more than half of your problems.
At the same time, if you resign and leave stating that you want to take care of your baby, then the question generally posed to women will be, "why didn't you think of this before availing maternity leave with salary when everyone knows that a baby of six months old will need the mother's care all throughout the day?" If all women start leaving the organizations that had provided them employment at a time when employment was very important to them than their families, then employers will also start thinking that let the women take care of their families, and we can refrain from hiring them. Should we give employers the opportunity to think like this?